Transistor quality checker with buzzer

You checked the transistor by measuring the resistance between the different pins. Sometimes it has problems, such as when measuring the resistance between the various legs correctly. But it does not work in the real circuit. Because while there is no measurement bias junction between CE. therefore, the detection transistor good or bad for sure. the transistors must be forward. and reverse bias at the same time. Injection of the electron, or hole between the junction. This circuit is a test. So, using the actual circuit. If the transistor test “good” circuit is the audio source it.

But if bad transistor. Integrated audio source will not come out. Or a very quiet voice. This circuit of operation of the simple astable transistors test to run during low flows about 20 mA,and transistors are tested to work with Q1 to generate frequency of about 2 KHz. the transistors Q2 expanding output to a buzzer. The switch S2 acts during the type test transistor NPN or PNP, the switch S1 using the press to test transistors.
http://www.hqew.net/circuit-diagram/Transistor-quality-checker-with-buzzer_10857.html

Over load protection for a transformer

The working principle of the circuit. Start step, dc voltage power from the secondary coil of the transformer will be charged to C1. through D1.When the switch S1 to the circuit, current flows through relay contact at the NC,And flowing through the load, R1 and VR1. The integrated parallel. by VR1 controls the power of the load and it is set the SCR1 to run, when the load current exceeded.
When overload occurs, SCR1 is triggered to work or inductor,The relay is running and contacts of relay are in NO position so The LED1 light . by the R2 reduces the current of LED1. The load is disconnected from the transformer. So now we have a current flowing through the coil of the relay SCR1, R1 and LED1 only.

After the relay function,If desired, the protection circuit is ready to work again, simply move S1 to the off position and move on again, or unplug it. Then reconnect. Protection circuit is ready to work the same.Do not forget, VR1 to adjust the load current is equal to the current transformers only. The D1, you will be using LED instead.Equipment to the power supply circuit with a maximum of 10 volts (no load). No filters to smooth flow, the use of a 1 amp transformer.

Measure the distance by bicycle

Operation of the circuit. Wreath switch S1 to detect the magnetic field. By S1 on the circuit.When a magnetic force drew near.When the magnetic field out away.It works in conjunction with resistors R1, R2 and capacitor C1.Pulse generator signal to IC1 to count pulses. When the pulse count to 8, the voltage is “high” from the pin 6, through R4, to stimulate the base pin of the transistor Q1 to work.
The current flowing through the LED, in Photocoupler IC2 transfer pulse output signal to Pin 7, 8. Into a series of modules, the frequency of the measurement distance is already installed on the bike.

The magnets are mounted on the cage wheel spokes, the wheel is about 12.5 inches from the center.The switch S1 wreath mounted bicycle stand tall, to meet with a magnet. When the magnet rotates around with S1 which is fully fit, or the origin of the pulse signal is a pulse. If the wheel rotates a full eight rounds, will have a pulse input to IC1, 8 pulses. The pressure to stimulate the transistors work, and displays the distance of one meter. If the wheel rotates around 9, or pulses 9, enter the IC1 is a reset, or start counting again until 8 around to show off to measure the distance. A second time. Each time it is displayed to a distance of 0.01 miles, or about 16 meters.

Source: http://www.hqew.net/circuit-diagram/Measure-the-distance-by-bicycle_10864.html

Flashing brake lights

This circuit will allow the brake light was flashing.The default behavior. When the power supply to the circuit, Or tap the brake it.The IC timer IC2 drive current to transistor Q2 and producing oscillator output, pulse signal output at pin 3 to input pin 1 of IC1. Count pulse and stops counting after 8 pulses, with pin 2 of IC1 is reset.
The transistor Q1 will trigger the IC2, and pin 3 of IC2 change status as well.The voltage drop across R3, the voltage at Pin 7 of IC2.
The Q2 has been a driving bias current, the LED brake lights.

Now, tap and hold the brake, the brake lights will flash the set, about 6 times per second.Which is determined by R3 and C3. The distance between each set, is defined by the C2 and R1. The Voltage input to the circuit,used 12 volt DC power from a car at all.The section capacitor C1 as a filter to smooth the flow. Transistor Q2 may be any number SM3180.
http://www.hqew.net/circuit-diagram/Flashing-brake-lights_10866.html

10 LED roulette with TC4011-LM4017

When entering the power supply circuit, and switch S1 (Start), which is attached press release switch off.Then current is flowing through R1, R2, and C2.
Makes the capacitor C2 caused up When the switch S1 allows the C2 to discharge through R3. The pressure this causes the clock input to the pin 8 of IC1a. The IC1a which will work with production IC1b frequency to send it to the leg 14 (Clock) Of IC2.The IC2 is a driver by ICs LED 10 is illuminated by the moon to the incoming frequency. The IC1d the IC1c and work together. It will serve up audio frequency generator, and then sent to the Piano Society (PZ1) loud beep came out with LED light period.


Reprinted Url Of This Article:
http://www.hqew.net/circuit-diagram/10-LED-roulette-with-TC4011$2dLM4017_10823.html

Simulate the traffic light circuit

You would never suspect. Traffic jam at the intersection. He do? Has opened the green light and red light. Or to have people turn off. To resolve the question, we try to create this same circuit.

LM7805

PT100

S82433NX

123NQ100

HEF4069

TAJA224M050RNJ

Operation of the circuit is IC1 (NE555) is the origin frequency pulse-mail rectangle out of pin 3, to define the operating environment of the IC2 (CD4027). The frequency of IC1 is based on the R1, R2, VR1,. VR2. The duration of the brightness of the green light Can be set by adjusting VR1. and if the adjustment will adjust VR2 time in light of the red light.Time signal that is sent to the IC2, which is connected to T-flip flop. The work is going to change the status every edge, rising of the signal pulse from IC1 by the IC2 to the signal output pins 15. But you can not drive the LED current directly, the IC3 (LM555) is used as a buffer circuit. To help drive Prasae the LED.This circuit works well. But there are disadvantages. The yellow light will be lit at all times.


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Tap tempo circuit using ic cd4011

This circuit will have an effect than Tap the rhythm circuit other because the whistle is giddy, which vividly than usual knock. You can also adjust the speed with 10-40 strokes per minute.
MC34063      ULN2003         74HC595         IRF3205        TDA2822      TDA7293

Operation of the circuit, we will be divided into three main parts of the schedule, the frequency generator, the control and amplify signals. The timing is IC1a, IC1b is a device to build up the frequency. This frequency is determined by R1, R2, C1, C2 and VR1. VR1 will be controlled by frequency And the frequency will be set of Q1, which works to affect Q3 Q1 Q3 to work intermittently The frequency generator is IC1c, IC1d frequency generator to drive out to the speakers. The frequency determined by the C3, C4, R5 and R6 signal will be expanded to drive the Q2 and Q4. But Q4 will not allow signals to pass the time. Q3 to control because it will work again in Q4. And Q5 connected with acts amplifiers to speaker, with a VR2 adjust the volume.


Reprinted Url Of This Article http://www.hqew.net/circuit-diagram/Tap-tempo-circuit-using-ic-cd4011_10816.html

TDA7294 Amplifier

---

The TDA7294 amplifier module is a monolithic integrated circuit. It is intended for use as an audio class AB amplifier in hi-fi applications. It has a wide voltage range and output current capability, enabling it to supply the highest power into both 4 ohm and 8n ohm loads. With the addition of a handful of parts and a suitable power supply, this module will deliver 50W RMS into 8-ohm with 0.1% THD.

You must supply a heavy duty heatsink rated at 1.4?C/W. Pin 10 is the MUTE input and pin 9 provides a STANDBY mode. Muting should always take place before standby mode is selected. Connecting these pins permanently to the supply rail (insert links) ensures that the amplifier comes on immediately on power up. Increasing the time constants R3-C6 and R4-C5 may eliminate any switch-on clicks. The IC has internal thermal protection that causes the mute to cut in at 145?C and switches the amplifier into standby at 150?C. Do not operate the module without a heatsink. The heatsink tab on the TDA7294 IC is internally connected to the negative supply rail. If the module is mounted inside an earthed metal enclosure then the IC must be insulated from the heatsink. If not, the negative supply rail will be shorted to ground.

Source: http://www.hqew.net/circuit-diagram/TDA7294-Amplifier_11422.html

TDA1011 6.5W Power Amplifier   The TDA1011 is a monolithic integrated audio amplifier circuit in a 9-lead single in-line (SIL) plastic package. The device is especially designed for portable radio and recorder applications and delivers up to 4 W in a 4 W load impedance. The device can deliver up to 6 W into 4 W at 16 V loaded supply in mains-fed applications. The maximum permissible supply voltage of 24 V makes this circuit very suitable for d.c. and a.c. apparatus, while the very low applicable supply voltage of 3,6 V permits 6 V applications. Special features are: ? single in-line (SIL) construction for easy mounting ? separated preamplifier and power amplifier ? high output power ? thermal protection ? high input impedance ? low current drain ? limited noise behavior at radio frequencies

TDA2030 - 14W Single Chip Power Amplifier

There are many instances where a very simple to build (and relatively cheap) power amplifier is needed. The TDA2030 is a single chip amplifier capable of 14W output into 4 ohms with a few external components.It can be used for almost any application you could think of.

The power from this amplifier is very average of many amplifiers, which means it could find applications anywhere, here are just a few ideas:

* A pair can form a capable amp for a stereo system (i.e. a home made or upgraded midi system or 'ghetto-Blaster', although battery operation will not be possible).
* This amplifier can be used to complete surround sound systems (i.e. center and rear channel amps). I used this amp for my center channel in my original surround sound system. It now lays unused, waiting for a mono audio application to present itself.
* A pair can be used to improve the sound from a NICAM? TV, or even one may be used to improve a mono TV.
* Beefing up those 400W amps in PC speakers (seriously)!
* Tweeter or mid range amplifiers in bi-amp or tri-amp systems.

S/PDIF to Analogue Converter

This is quite possibly the simplest S/PDIF receiver and DAC available. It uses the absolute minimum of parts, and also minimises the connections and control functionality usually provided. It is still a serious project, and is not recommended for beginners. As shown, the connection is COAX (but will almost certainly handle TTL just as well). If you want a dedicated TTL to COAX converter, there is an adapter shown at the end of this article. The spare gates in the 74HC04 package may be used for the adapter if desired.

 

Read more at http://www.hqew.net/circuit-diagram/S$2fPDIF-to-Analogue-Converter_11424.html

Variable Voltage / Current PS   This regulated power supply can be adjusted from 3 to 25 volts and is current limited to 2 amps as shown, but may be increased to 3 amps or more by selecting a smaller current sense resistor (0.3 ohm). The 2N3055 and 2N3053 transistors should be mounted on suitable heat sinks and the current sense resistor should be rated at 3 watts or more.

http://www.hqew.net/circuit-diagram/Variable-Voltage-$2f-Current-PS_11382.html

Precise Low Voltage Power Supply   This power supply eliminate voltage loss on current meter. Will be designed for measure on low voltage DC/DC converters (e.g. LED lamps powered from single NiCd/NiMH cell)

The Capacitance Multiplier

The power supply for the original 1969 JLH design included a form of capacitance multiplier to reduce the amount of voltage ripple on the supply rail. The capacitance multiplier circuit has been developed further, by Rod Elliott of Elliot Sound Products, and the results published as Project 15 at the ESP Audio Pages. The modified circuit is suitable for both the original 1969 JLH amplifier (using only the positive half of the circuit) and the 1996 update. The design considerations for the capacitance multiplier, its benefits, and a comparison with voltage regulators are included in the Project article.

Reprinted Url Of This Article: http://www.hqew.net/circuit-diagram/The-Capacitance-Multiplier_11388.html

12 volt power supply using LT3845

Using the LT3845 is high voltage, synchronous, current mode controller can be designed a high efficiency 12 volt power supply .
An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN.
Burst Mode operation maintains high efficiency at light loads by reducing IC quiescent current to 120μA. Light load efficiency is also improved with the reverse inductor current inhibit function which supports discontinuous operation.

Additional features include adjustable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, 10μA shutdown current, short-circuit protection and a programmable soft-start.
This 12 power supply project will require an input voltage range between 20 and 55 volts and will deliver a maximum output power of 75 watts at 12 volts output voltage .
Using the LT3845 high voltage controller you can design various power applications , because this controller accepts a wide input voltage range between 4 and 60 volts and can provide a maximum output voltage around 36 volts . Also LT3845 has an adjustable constant frequency from 100kHz up to 500kHz .
Source: http://www.hqew.net/circuit-diagram/12-volt-power-supply-using-LT3845_7283.html

5 volt DC power supply using LTC3833 regulator

A very simple step down DC converter electronic project , can be designed using the LTC3833 , manufactured by Linear Technology . The LTC3833 is a synchronous step-down DC DC switching regulator controller targeted for high power applications. It drives all N-channel power MOSFETs. The controlled on-time valley current mode architecture allows for both fast transient response and constant frequency switching in steady-state operation, independent of VIN, VOUT and load current.
As you can see in the schematic circuit , this step down DC converter design , require few external electronic components .
This step down DC converter require an input voltage between 7 volt and 38 volt and will provide a fixed 5 volt DC at a maximum output current of 8 amperes .
As you can see in the diagram bellow , the efficiency of this step-down Dc converter is very high . You can use this 5 volts DC converter circuit for applications like datacomm systems , computing systems or some other electronic projects where is needed a high precision low output voltage at a huge output current .

Some features of the LTC3833 switching regulator are : wide VIN Range: 4.5V to 38V , VOUT Range: 0.6V to 5.5V ,differential output sensing allowing up to 500mV line loss , fast load transient response ,frequency programmable from 200kHz to 2MHz , overvoltage protection and current limit foldback , power good output voltage monitor and more .

15A switching power supply using LTM4627

Using the LTM4627 integrated circuit designed by Linear technology you can design a very simple , high efficiency 15A switching power supply . Because the LTM4627 switch mode circuit include in the package almost all components required : switching controller, power FETs, inductor and compensation components , this high power switch mode DC regulator IC require few additional external electronic components .
This switch mode power supply circuit has a wide input operating range from 4.5V to 20V,and will provide a very stable output voltage range of 1.2 volt . The LTM4627 supports an output voltage range of 0.6V to 5V, set by a single external resistor , so you can modify the output voltage .
High switching frequency and a current mode architecture enable a very fast transient response to line and load changes without sacrificing stability. The device supports frequency synchronization, multiphase/current sharing operation, Burst Mode operation and output voltage tracking for supply rail sequencing.
Because the value for the output capacitor depends of output voltage please take a look in the datasheet at table 4 ( just if you modify the design ) .

NCP571 low power regulator

• Power Supplies Circuits

In some electronic projects you will need an unusual regulated voltage , unusual , because the voltage required is very small and you can not use zenner diodes or some other tricks due of a compact design . In that case you can use this voltage regulator circuit based on the NCP571 , NCV571 which are low current voltage regulators available in few standard output voltage versions ( 0.8 V, 0.9 V, 1.0 V and 1.2 V ) .
The NCP571 , NCV571 low dropout linear regulators are designed for handheld communication equipment and portable battery powered applications which require low quiescent current. The NCP571 , NCV571 series features an ultra?low quiescent current of 4.0 uA.
NCP571 , NCV571 device contains a voltage reference unit, an error amplifier, a PMOS power transistor, resistors for setting output voltage, current limit, and temperature limit protection circuits.
The maximum output current that can be delivered by NCP571, NCV571 low dropout linear regulators is around 150mA , enough for handheld devices .

Microprocessor and Microcontroller

When you start learning aboutMicroprocessors(in most case you will begin with Intel 8085) andMicrocontrollers(usually you will begin with Intel 8051 from the MCS 51 micro controller family), the first question that pops up is“hey… what’s the difference in between” ?In this article I am explaining the basic differences and similarities between a microprocessor and micro controller. In fact you can call this article a simple comparison of both micro computing devices. This comparison will be same (at the basic level) for any micro processor and controller. ?So lets begin.

At the basic level, a microprocessor and micro controller exist for performing some operations – they are – fetching instructions from the memory and executing these instruction (arithmetic or logic operations) and the result of these executions are used to serve to output devices. Are you clear? Both devices are capable of?continuously?fetching instructions from memory and keep on executing these instructions as long as the power is not turned off. Instructions are ?electronic instructions represented by a group of bits. These instructions are always fetched from their storage area, which is named as memory. ?Now lets take a closer look at block diagrams of a microprocessor based system and a micro controller based system.

Microprocessor based system

Take a closer look at the block diagram and you will see a micro processor has many support devices like Read only memory, Read-Write memory, Serial interface, Timer, Input/Output ports etc. All these support devices are interfaced to microprocessor via a system bus. So one point is clear now, all support devices in a?microprocessor?based system are external. ?The system bus is composed of an address bus, data bus and control bus.

Okay, now lets take a look at the microcontroller.

Micro controller system

The above block diagram shows a micro controller system in general. What’s the primary difference you see? All the support devices like Read only memory, Read – Write memory, Timer, Serial interface, I/O ports are internal. There is no need of interfacing these?support?devices and this saves a lot of time for the individual who creates the system. You got the basic understanding ? A micro controller is nothing but a microprocessor system with all support devices integrated inside a single chip. There is no need of any external interfacing in a micro controller unless you desire to create something beyond the limit, like interfacing an external memory or DAC/ADC unit etc. To make this microcontroller function, you need to give a DC power supply, a reset circuit and a quartz crystal (system clock) from external source.

Okay, so we have an idea about the basic difference between a microprocessor and microcontroller. Now lets compare some features of both systems.

Comparison

As you already know, support devices are external in a microprocessor based system where as support devices are internal for a micro controller. Micro controllers offer software protection where as micro processor base system fails to offer a protection system. This is made possible in microcontrollers by locking the on-chip program memory which makes it impossible to read using an external circuit. Okay! So that are basic differences, now you can come up with some more. As we need to interface support devices externally in a microprocessor based system, time required to build the circuit will be more, the size will be more and power consumption will be more in a microprocessor based system compared to microcontroller.

Source: http://www.hqew.net/circuit-diagram/Microprocessor-and-Microcontroller-_10102.html

2012 Welcomes 3D Transistors!!

 

3D Transistor

A transistor is the fundamental building block of all electronic devices. ?.? A transistor can be defined as a device, which is used to amplify signals and power. Integrated circuits are used in making of chips inside electronic gadgets such as smart phones, laptops and so on. Researchers in Purdue and Harvard Universities have created a new type of transistor that will make the Integrated circuits more compact. This transistor is made from another material other than silicon and as the name suggest, a 3-D structure is given to the device compared to the conventional flat chips. Nano wires are used in these transistors instead of silicon so they will be more compact and more efficient. The nano wires used in this transistor are made from iridium gallium arsenide semiconductor.

Iridium-gallium-arsenide is replaced for silicon in this device. As they are elements from the 3^rdand 5^thgroup of the periodic table, they are collectively known as the III-V group semiconductors. These semiconductors are known to conduct electrons five times better than silicon. The mobility of this material is also known to be higher. All these characteristics have urged chip manufacturers to replace silicon with this semiconductor in the coming years.

The 3D transistor was made by a process termed ”top- down method” in which components of the transistor is etched. This method will gain huge acceptance as it is compatible with most of the industrial processes. In 2012, a new generation of integrated chips is believed to come into market in which transistors will be placed horizontally rather than vertically. This is the reason for the 3D effect posed by these transistors. Thus, this device is the world’s first 3D-gate-allround transistor

Read the rest at http://www.hqew.net/circuit-diagram/2012-Welcomes-3D-Transistors!!_10104.html

Stealth Paint to Make Airplane Invisible

 

Carbon Nanotube Coating

Radar detection has always been the nightmare of military aircrafts. Once spotted in the radar zone, it is easy to destroy the aircraft in mid air by using anti-aircraft missiles. Defense personnel’s across the world are investing billions to develop better stealth equipped aircrafts that will easily escape from radar eyes. ?The concept of stealth is applied on an aircraft by making changes in the aircraft design such that it deflects the radar beams instead of reflecting them. The aircraft design is such that there are no perpendicular sections in the body of the plane, so the radar beam never reflects back to the receiver. ?While making a stealth aircraft we have to compromise with one of its main factor – the engine power. Though reducing the engine power can reduce the heat signature, the speed of the aircraft will also be compromised. ?What if we could develop a better stealth technology without compromising the aircrafts’ speed? ?We are talking about a technology that will make any aircraft invisible for radars.

Researchers have invented a special nano tube paint to make any object ultra black. This concept is also used for making aircrafts invisible to radars.

Engineers of NASA developed carbon nano tubes, being the ‘blackest ‘known material for their space missions. Carbon nano tubes will absorb 99 percent of any light- ultraviolet, visible or infrared that strikes on it. The material is also known for its excellent electrical conductivity and high strength .Carbon nano tubes are tiny yet long tubular structures made of pure carbon. ?A professor from Michigan University L J Guo first realized that by applying the nano paint or the nano tube coating, the aircraft could absorb the radar waves there by making it virtually invisible.

The researchers implanted large volumes of nano tubes into various substances like silicon wafer. Nano tubes have to be planted in a particular manner to make its reflective index similar to surrounding air. After implantation, the light is absorbed without being scattered. A practical method to implant nano tubes on the surface of aircrafts has not been developed until now. Perfect results were obtained only when nano tubes were implanted in tiny particles under the influence of high temperature and pressure. Guo suggested that first, the nano tubes has to be implanted in tiny particles and then suspended in the paint for stealth aircrafts. Earlier, to prevent absorption and radioactive properties, a metallic mixture was added to black paint and then coated on the aircraft. However, this would add excess weight to the machine. Since nano tube has ultra black property? and is denser, there is no need of any additives.

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FET Overload Current Trip

Circuit FET Overload Current TripNormally the thing that is worried of power supply circuit , be the occurrence through the circuit of load. Which can happen always. We come to see the circuit FET Overload Current Trip help can protect. By use important equipment is FET pay current give with load. When be born system problem. Will a bunch catches exceed trend cut voltage give with load. Get immediately and have SW1 perform be switch reset the work is new. For VR1 use fine the rapidity of the checking current exceed sir. The detail is other see in the circuit adds sir.

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Overload protection circuit Generally the level of a signal that departs output of sound signal generator the all. The that get fix have standard same score be 1Vrms. [...]
Over voltage and low voltage protection circuit This is an electrical circuit protection device sound disappeared, when too much voltage 220V, and protection, when pressure is too low with Using the relay cut off power when voltage problems.[...]
Fuse electronic for ic regulator Normally the thing that is worried of power supply circuit , be the occurrence through the circuit of load. Which can happen always. We come to see the circuit FET Overload Current Trip[...]

Reprinted Url Of This Article: http://www.hqew.net/circuit-diagram/FET-Overload-Current-Trip_10200.html

Low Battery Voltage Indicator by IC 8211

CircuitLow Battery Voltage Indicator by IC 8211
This be Low Battery Voltage Indicator circuit, model easily. It can show the level voltage , minimum of battery get with LED. By use IC number IC 8211 or ICL 8211 (Programmable Voltage Detectors) when voltage of power supply lower arrive at the dot that fix ( but do not lower 1.15V). The Voltage Comparator circuit within IC 8211 as a result will order give the circuit gives current come out drive LED1 stick bright get. This circuit uses current altogether about 7mA only and can set voltage minimum get with VR1. Besides still use a little equipment 4 pcs. can work already. You see the detail in the circuit.
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5 Channels 2 Octave Graphic Equaliser by 4558

This circuit 5 Channels 2 Octave Graphic Equaliser,easy to make equalizer,
because using IC 4558 or 1458 or LF353 (nice)
If you are seeking Graphic Equalizer Circuit at can fine decorate the sound of music has full frequency sound section. As a result try out group this circuit before. May don’t be defeated.Cut at frequencies of 50Hz, 200HZ,800Hz,3.2kHz and 12kHz.
Supply voltage may be anything from -15V GND -15V for IC 4558.
Besides I still lead model PCB try build can be usable easy increasingly sir.

PCB 5 Channels 2 Octave Graphic Equaliser by 4558
Related Links
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Dfferential Temperature Relay Switch by IC 741

Dfferential Temperature Relay Switch by IC 741
This is Circuit Dfferential Temperature Relay Switch .
Use IC 741 for control relay ad Diode D1,D2 for sencer Temperature . VR1 for adjusable voltage.


Source: http://www.hqew.net/circuit-diagram/Dfferential-Temperature-Relay-Switch-by-IC-741_10203.html

Mini Trombone Sound generator by LM3909

This be Mini Trombone Sound generator circuit. By using integrated circuit the number LM3909 of NS. In using loudspeaker 25 Ohm sizes work by use voltage from AA 1.5V battery. In sound occurrence that resemble with trombone.
It have the work depends on the principle uses voltage, which the generator by the occurrence Resonance of sound coil of a loudspeaker is feeding gets back to the way adds to give with integrated that circuit was set up in large-sized box,which there is the capacity about 64 inch cubic which one side of a box has can to move in and out resemble a cylinder a position of a piston.
The work of switch press will cause the tone of voice that resemble very integrated loudspeaker circuit and battery touch set up on a piston , which there are 5 size inch pipes. For be born air push reaches and go out while a piston moves by don’t affect to build the frequency Resonance. The frequency of origin frequency circuit will begin to equal to the frequency Resonance of a box.

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Mini intercom by one ic op-amp

This is mini size intercom circuit. It uses IC Op-amp number LM380 just one as a result can work already. When switch S1 stay in a position speaks loud show in circuit picture. The loudspeaker of mother station will perform to is microphone for drive op-amp. By change step up transformer or T1. The switch of child station will must is in a position listens. The voltage of power supply stay in 8-20Volt sections.

LM390 MiNi Intercom oday we find many of the IC number LM390 in the old tool box. I see that my son is boring, and do not want him sitting to play the games computer all day so have new ideas. Let’s make up an small intercom projects with old equipment. [...]
IntercomThis circuit was requested by an school teacher. It is a simple intercom that anyone can put together and get to work. It is based on the LM380 IC chip. This chip is able to put out 2 watts of power if it is heat sink properly. The following pins should be grounded and attached [...]
Door phone Intercom by IC LM386 For the first time, this circuit was designed by two authors, Mr Laurier Gendron of Burnaby in British Columbia, Canada, and myself. Please make sure you visit Laurier’s web site, Handy Dandy Little Circuits. This page is also available in French by clicking on the flag. In this doorphone circuit,an 8 ohm speaker is used [...]

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Fuzz audio converter using LM324

This is Fuzz audio converter circuit. By use diode 2 pcs. in feedback circuit of OP-AMP IC , number LM324. I make for build way music sound that have unusual character. By limit output voltage , give a hand net between 0.7Vp-p waves square signal that is the result that is will proportionate big compose harmonic be the odd number , resemble the sound of a donkey. The Resistor at use fine the depth of fuzz audio. It will use fine the level that want to is born top waves slitting goes up. And the resistor at use fine the intensity of output signal. The detail is other , see in circuit picture.

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How to build Periodic Timer

Description:

A switched timer with equal make and equal space periods timing adjustable from over 6 minutes to 38 minutes.

Circuit diagram:

Notes:

This timer circuit is similar to the 5 to 30 minute timer except that when switch S1 is closed, the on/off action of the circuit will continue indefinately until S1 is opened again. A 7555 time and low leakage type capacitor for C1 must be used. The 6 way rotary switch S3 adds extra resistance in series to the timing chain with each rotation, minimum resistance point "a" maximum point "f". The 7555 is wired as an equal mark/space ratio oscillator, the timing resistor chain R1 to R6, being connected back to the output of the timer at pin 3.The output pulse duration is defined as:-
T = 1.4 R1 C1
This gives on and off times of about 379 seconds for postion "a" of S3 (just over 6 minutes), to about 38 minutes at point "f". The times may of coourse be varied by altering R1 to R6 or C1.

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How to build 4W FM Transmitter

TECHNICAL CHARACTERISTICS:

• Stabilised tendency of catering: Vcc=12~16V
• Frequency of emission: 88~108MHz
• Consumption: 100~400mA

Circuit diagram:

Materially:

• The resistors are 1/4W.
• R1, R2 10KOhm
• R3 47Ohm
• C1, C2 1nF
• C3 4,7uF/16V
• C4, C7, C8 0~45pF trimmer
• C5, C6 10pF
• C9 100nF
• L1 4 turns, 7mm diameter *
• L3 3 turns, 7mm diameter *
• L4 5 turns, 7mm diameter *
• L2 RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)
• T1, T2 2N2219
• ANT Simple dipole l/2.
• MIC IN Microphone dynamic or other type. (It can also connected to a cassette player unit)
• * The inductors is air from wire of coaxial 75W or other 1mm roughly.

PCB:

Before you print it out with microsoft paints, set the screen resolution to 1280 by 1024 in order to get the correct scale

Regulations:

• With the C4 we regulate the frequency.
• With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner).

Notes:

The T2 wants refrigerator.

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How to build 220 Volts Flashing Lamps

Especially designed for Christmas tree lamps
Replaces old thermally-activated switches

Circuit diagram

Parts:

• R1 100K 1/4W Resistor
• R2,R5 1K 1/4W Resistors
• R3,R6 470R 1/4W Resistors
• R4 12K 1/4W Resistor
• C1 1000μF 25V Electrolytic Capacitor
• D1-D4 1N4007 1000V 1A Diodes
• D5 P0102D 400V 800mA SCR
• Q1 BC327 45V 800mA PNP Transistor
• Q2 BC337 45V 800mA NPN Transistor
• PL1 Male Mains plug
• SK1 Female Mains socket

Device purpose:

This circuit is intended as a reliable replacement to thermally-activated switches used for Christmas tree lamp-flashing. The device formed by Q1, Q2 and related resistors triggers the SCR. Timing is provided by R1,R2 & C1. To change flashing frequency don't modify R1 and R2 values: set C1 value from 100 to 2200μF instead.
Best performances are obtained with C1=470 or 1000μF and R4=12K or 10K. Due to low consumption of normal 10 or 20 lamp series-loops intended for Christmas trees (60mA @ 220V typical for a 20 lamp series-loop), very small and cheap SCR devices can be used, e.g. C106D1 (400V 3.2A) or TICP106D (400V 2A), this last and the suggested P0102D devices having TO92 case.

Important Note:

For proper operation it's absolutely necessary to employ high Gate-sensitive SCRs. If you are unable to find these devices you can use Triacs instead. In this case the circuit operates also with relatively powerful devices. A recommended Triac type is the ubiquitous TIC206M (600V 4A) but many others can work.Note that in spite of the Triac, diode bridge D1-D4 is in any case necessary.
This circuit was awarded with publication in ELECTRONICS WORLD "Circuit Ideas", June 2000 issue, page 458

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How to build Magic Wand Conjuring Trick

The simple conjuring trick in Figure 1 is intended to provide some enjoyment for the beginner in electronics or conjuring, and should take only an hour or two to build.

Circuit diagram

The trick works as follows: a wand (with a magnet mounted in one end) must pass in a 1-2-3 sequence over reed switches S4 to S6 before the bulb LP1 will light. If the wand passes over reed switches S1, S2, or S3, the 1-2-3 sequence will be reset (that is, cancelled). Or, if the bulb is already burning, the activation of reed switches S1, S2, or S3 will extinguish it.
All the reed switches - S1 to S6 - are glued just beneath the surface of a 10 cm² box (Figure 2). A general purpose adhesive is suggested, so that the reed switches may later be moved if necessary. The bulb, LP1, is mounted in the centre of the box. A small PP3 9V battery may be used. The prototype box was built using balsa wood.
The wand may be waved back and forth in various motions over the box, on condition that it finally passes in the correct 1-2-3 sequence over S4 to S6 (at which point LP1 will light). This should thoroughly confuse any onlooker and make it virtually impossible for another person to repeat the correct motions with the same wand. The wand may also be lifted just high enough over reed switches S1 to S3 so as not to trigger them.
A 7.2V filament bulb, LP1, was used - instead of, say, a LED - so as not to give the trick an "electronic" appearance.
The operation of the circuit is fairly simple. Three AND logic gates of a 4081 CMOS IC are employed, with gates IC1a to IC1c being configured as a standard cascaded latch circuit. S1 to S3 serve as reset switches. The output at pin 10 will only switch to logic high when reed switches S4 to S6 are closed in sequence. Power transistor TR1 amplifies the output current to light bulb LP1.
Instead of a wand, a small neobdymium (super-strength) magnet may be stuck to one finger, and one's finger used in place of the wand.
In "stand-by" mode (with the bulb extinguished) the circuit will use very little current. Therefore a switch is not included in the circuit (of course, one may be added). The box may be opened and the battery simply clipped on or off.
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Transimpedance amplifier

Transimpedance amplifier / current to voltage converter.

The transimpedance amplifier is a circuit that converts current to a proportional voltage. It is also termed as current to voltage converter or simple I to V converter. The transimpedance amplifier has ideally zero input resistance and low output resistance. The transconductance amplifier has a lot of applications in day to day electronics. For example, converting to current detected by a photo diode into a proportional voltage, digital to analog converter (DAC) applications etc. Current to voltage converters are of two types, passive and active.

Passive current to voltage converter.

As the name indicates, only passive elements are used for implementing the circuit. The circuit diagram of a passive current to voltage converter is shown below. Here the resistor R converts the current I from the current source into a proportional voltage across R itself. The mechanism follows Ohm’s law (V= IR).

Passive current to voltage converter.

Anyway the passive current to voltage converter has many limitations. For the proper operation, the input current source and the output load must be ideal. That means the output load resistance must be close to infinity, the current from the current source must be independent of the voltage created across load resistor ( current source must have unlimited capacity) and also the current source must have infinite internal resistance. These conditions are practically impossible to attain and so passive current to voltage converters are seldom used in practical applications.

Active current to voltage converter ( transimpedance amplifier).

An active current to voltage converter (transimpedance amplifier) is based on active elements like BJTs, FETs or an opamp. Transimpedance amplifier using opamp is the commonly used one. The circuit diagram of an opamp based current to voltage converter is shown below.

Active transimpedance amplifier circuit

In the circuit diagram V and V- are the voltage sources for the opamp. Rf is the feedback resistor and RL is the load resistor.

Expression for the output voltage.

The equation for the output voltage of the opamp based current to voltage converter can be derived as follows. The opamp here is wired in closed loop inverting mode with feedback resistor = Rf. ?Let iIN be the input current that needs to be converted and Vout be the output voltage of the converter circuit.

The equation for the voltage gain (Av) of an opamp inverting amplifier can be written as,

Av = – Rf/R1.
Therefore Vout = -(Rf/R1) (Vin)……….(1)
Since non inverting input is connected to ground and the ideal opamp has infinite input resistance, we can assume V1 = 0 and V1=V2.
Also i IN = Vin/R1……………………………(2)
Substituting (2) in equation (1) we get
Vout = -(i IN) ( RF)
In simple words, a current to voltage converter using opamp is made by replacing R1 and Vin of an opamp inverting amplifier and replacing it with a current source i IN.

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2×5 W Stereo power amplifier circuit based on BA5417.

BA5417 stereo power amplifier.

BA5417 is a stereo amplifier IC with a lot of good features like thermal shut down, standby function, soft clipping, wide operating voltage range etc. The IC can deliver 5W per channel into 4 ohm loud speakers at 12V DC supply voltage. The BA5417 has excellent sound quality and low THD (total harmonic distortion) around 0.1% at F=1kHz; Pout=0.5W.

Description.

Setup and working of this stereo power amplifier circuit is somewhat similar to the BA5406 based stereo amplifier circuit published previously. C10 and C11 are DC decoupling capacitors which block any DC level present in the input signals. C2 and C6 couples the amplifiers left and right power outputs to the corresponding loud speakers. C1 and C5 are bootstrap capacitors. Bootstrapping is a method in which a portion of the amplifiers is taken and applied to the input. The prime objective of bootstrapping is to improve the input impedance. Networks R1,C3 and R2,C7 are meant for improving the high frequency stability of the circuit. C4 is the power supply filter capacitor. S1 is the standby switch. C8 is a filter capacitor. R3 and R4 sets the gain of the left and right channels of the amplifier in conjunction with the 39K internal feedback resistors.

Circuit diagram.

BA5417 stereo amplifier circuit

Notes.

• Supply voltage range of BA5417 is from 6 to 15V DC.
• The recommended supply voltage for this circuit is 12V DC.
• The power supply must be well regulated and filtered.
• BA5417 requires a heatsink.
• The circuit can be assembled on a perf board without much degradation in performance.

Few other stereo amplifier circuits that you may like.

BA5406 stereo amplifier circuit: Simple stereo amplifier circuit that can deliver 5 watt per channel sound output into a 4 ohm speaker. Operates from 12V DC and requires very few external components. Suitable for low power car audio applications.

TDA1554 stereo amplifier circuit: ?A very popular stereo amplifier design. This amplifier can output 22 watts per channel into 4 ohm loud speakers. This circuit can be also powered from 12V DC. Low distortion and noise.

2×32 watts stereo amplifier circuit: High quality stereo amplifier design using TDA2050 IC. The circuit requires a /-18V DC dual supply. Power output is 32 watts per channel into 4 ohm speakers.

Stereo amplifier based on TDA4935: A stereo amplifier design with a lot of great features like over load protection and thermal shut down. The power out put is 2×15 W into 4 ohm speakers. Operating voltage is 24V DC. Potentiometers for controlling the volume is also included in the circuit.

120W stereo amplifier circuit: A powerful stereo amplifier design using LM4780 audio amplifier IC from National Semiconductors. operates from a /-35V DC dual power supply. 2×60 watt power output into 8 ohm loud speakers. The circuit has good power supply rejection and also there is a built in mute circuitry.

See a Robot Workout!!

Petman

Boston Dynamics, an engineering company founded by Marc Raibert and his colleagues in the year 1992, have developed dynamic robots and its software for human simulation. Several innovations were made by them college life in Massachusetts Institute of Technology. They excelled in the field of robotics and developed robots that could run and epitomize all basic characteristics of animals.

Lately, the researchers at the Boston Dynamics lab developed an anthropomorphic robot called Petman. It is a two-legged, upright robot designed to stand and walk like a man. The main aim of the machine is to test chemical warfare clothing for the US army. The robot replicates the same motion of a human being and is able to move at a speed of 3.2 miles/hour.

Besides the regular motion of the robot, it has also been programmed to demonstrate some basic workout methods like – treadmill walking, push-ups, squats, lunges and some simple calisthenics. From the video below, you can see the robot balancing itself when it is pushed while running on the treadmill.

It took almost 15 months for the designers to design this wonderful machine, and 15 more months to build it.

Lab Grown Blood Successfully Experimented on a Human

Red Blood Cells

Luc Douay, a researcher at the Pierre and Marie Curie University in Paris was successful in creating artificial red blood cells in a lab. The researchers were also able to inject it into a human and the results were positive without any side-effects.

A healthy volunteer was first selected for the program, and his hematopoietic stem cells were extracted from his bone marrow. Some of the basic growth factors that are required for the growth of a red blood cell were also mixed with this sample. Luc’s team labelled these cultured cells for tracing, and injected 10 billion of them (approximately equal to two millilitres of blood), back into the same donor’s body.

They found out that almost the whole percentage of blood cells remained circulating in the body for the first five days. Like in the case of naturally produced red blood cells, about (45-65)% of the blood cells remained in the body after 26 days of experimentation. As no serious conditions were registered for a month after the experiment was conducted, it was sure that the red blood cells injected were working like a normal blood cell, and carried the oxygen around the whole body.

This experiment is sure going to be a stepping stone to further technologies, and a clear way to produce an artificial blood reserve without the help of any blood donor. Though the numbers of blood donors have increased in the past couple of years, their reserve list is still short in some parts of the world, where the number of people suffering from HIV and blood cancer are comparatively more.

There are also researches going on in developing an artificial blood substitute that is known to be less toxic than the protein in its unbounded state. Such a substitute was first developed by Chris Cooper of the University of Essex in Colchester. He was able to develop a haemoglobin based blood substitute that could easily provide a solution for transfusion in worst cases like natural disasters, and combat fields. The main advantage of such a system is that there is no need to store it in a cool place like a fresh and stem cell-grown blood.

But the former technology has more advantages than this one. Since the blood grown through stem cell method resembles a real blood cell, it can easily alleviate some of the safety concerns that continue around the use of the current generations of artificial products.

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10A Adjustable voltage Regulator

10A Adjustable voltage Regulator MSK 5012.

MSK5012 is a highly reliable adjustable voltage regulator.Whose output can be programmed using two resistors. The regulator has a very low dropout voltage(0.45v @10A??)due to the usage of MOSFET with very low Rds (ON) as the internal series pass element.The MS5012 has a high level of accuracy and ripple rejection is around 45dB. It is available in a 5 pin Sip package that is electrically isolated from the internal circuitry. This give us the freedom to fit the IC directly to the heat sink and this sort of direct heat sinking improves the thermal dissipation.

Description.

The output voltage of this circuit is adjustable from 1.3v to 36v DC.Resistors R₁and R₂are used for programming the output voltage.For all applications, value of R₂is fixed to 10K. The relationship between R₁,R₂and output voltage Vout is according to the equation R₁=R₂(Vout/1.235)-1. C₁is a filter capacitor which is also a part of the gate drive circuit of the internal series pass MOSFET. Around three times the input voltage will appear across this capacitor and so the its voltage rating must be selected accordingly.C₂is the input filter capacitor while C₃is the output filter capacitor.

Circuit ?diagram.

10A adjustable voltage regulator MSK5012

Notes.

• Input voltage 3v to 36v DC.
• Output voltage range 13v to 36v DC.
• Typical application of MSK5012 are high efficiency linear regulators, constant voltage/current regulators, system power supplies etc.
• A heat sink with thermal resistance not more than 2.40?^oC/W must be fitted to the MSK5012.
• Resistance R₂is fixed at 10 K for all applications.
• Quiescent current of MSK5012 is around 10mA.

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Regulated DC power supply

Regulated DC Power Supply using transistors.

A low ripple regulated DC power supply designed based on transistors is shown here. Such transistor voltage regulators are suitable for application where high output current is required. Conventional integrated series regulators like 7805 can only deliver up to 1A. Additional series pass transistors have to be added to the 7805 based regulator circuit for improving their current capacity.

Description.

The circuit shown below is a basic series voltage regulator based on transistors. Transistor Q1 (2N 3054) and Q2 (2N 3055) form a darlington pair. Resistor R1 provides the base current for Q1 and also keeps the zener diode D2 in the active region. The overall working of the circuit can be demonstrated by explaining two situations.

• When the input voltage (output of the rectifier section) increases, the output voltage of the regulator (Vout) also increases. This increase in Vout decreases the base emitter voltage of Q2 because the zener diode D2 is operating in the breakdown region and the voltage across it is unchangeable. This decrease in V_BEincreases the collector emitter resistance? of Q2 and so the output voltage (Vout) gets reduced accordingly.
• When the output load increases, the output voltage (Vout) gets reduced. This decrease of output voltage (Vout) makes V_BEof Q2 to decrease. This reduces the collector emitter resistance of Q2 and so the output voltage gets increased accordingly.

Circuit diagram.

Regulated dc power supply

Notes.

• If 5A bridge is not available, then make one using 6A6 diodes.
• Transistor Q2 requires a heat sink.
• An optional 5A fuse can be added in series to the output.
• Breakdown voltage of the zener diode D2 must be chosen according to the output voltage you need, and it is according to the equation, Vout = Vz – 0.7.

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Class AB amplifier 12V

Class AB Audio Power Amplifier.

Class AB amplifier is an amplifier configuration that stands somewhere between Class A and Class B configurations. A small diode biasing voltage keeps the output transistors ON even if there is no input signal. The transistors will operate normally in their active region for any small input signal.In simple words, one transistor will be ON for more than one half cycle of the input signal.? This avoids crossover distortion. Anyway, a small amount of collector current will flow in the idle condition, but it is negligible when compared to the Class A configuration. .?A simple, high quality audio power amplifier that can be operated from 12V dc is shown below. Such an amplifier is very suitable for car audio applications. The circuit is very straightforward and uses commonly available components. Power output of this amplifier is around 10W.

Description.

The circuit is purely based on transistors. The first stage of the circuit is the long tailed pair (LTP) built around the transistors Q1 and Q2. Transistors Q10, Q11 and associated components form a constant current source for the long tailed pair. Resistors R15 and R3 are biasing resistors. The second stage of the circuit is built around transistor Q3. Transistors Q9 and Q6 form a constant current source for the second stage. Resistor R8 is the feedback resistor and it plays a vital role in reducing distortion. The final power amplification stage of the circuit is based on the complimentary pairs Q8 and Q5. Q7 and Q4 are the driver transistors for Q8 and Q5 respectively. Audio output is coupled to the loud speaker through capacitor C3.?D1 and D2 are biasing diodes. C4 is the power supply filter capacitor. This amplifier circuit can be operated from anything between 12 to 16 volts.

Circuit diagram.

Class AB amplifier

Notes.

• Use 12V DC for powering the amplifier.
• An optional 10K POT can be added in series to the input for volume control.
• Use a 4 ohm/20W speaker as the load.
• Transistors Q8 and Q5 must be fitted to a proper sink.

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