Voltage Quadrupler

Circuit Description:

This circuit uses some diodes and capacitors to generate 57 V from an 15 V input signal.

Mismatched transmission lines (Pulse)

Circuit Description:

This is a simple circuit showing three mismatched transmission lines. The two lines on the end are 75 ohms, and the middle line is 500 ohms. Waves traveling down the line are reflected at transmission line boundaries.

Impedance Matching (L-Section)

Circuit Description:

This is an example ofimpedance matching. Twotransmission lineswith differentcharacteristic impedancesare matched with an inductor and a capacitor, eliminating standing waves in the first line. On the bottom you see the same two lines without impedance matching. The power delivered to the load is graphed for both cases on the bottom. With impedance matching, more power is delivered to the load.

LED testing tool

Everyone who works with LED's need to know what colour is the LED, how much current it needs to shine the best, what resistor is needed.

Simple universal microphone preamplifier

Microphone preamplifier is a circuit that stands between microphone and stereo amplifier. You just need to connect microphone to circuit input while output can be connected directly to line/CD/aux/tape inputs.

Non-isolated AC to DC power supply

This simple power supply circuit can reduce any voltage from 20vac to 120vac into 5 volts DC and can provide current up to 100mA.

DC servo motor driver

Servo motor is a motor controlled by pulses. It positions it's shaft depending on received pulses. This circuit's heart is PIC16C71 microcontroller. Potentiometers are used to control the rotation of the servo motor. Sadly the author didn't provide the code, so you can experiment with the circuit by writing your own code.

12V solar charger using LM317

[Alex] decided to build a solar charger for his car battery. He had an 18V solar panel able to provide up to 83mA. You cannot connect panel directly to battery because charging voltage cannot exceed allowed safe limit and also solar panel may become as load for battery in dark time and this way discharge it.

So he ended up with simple circuit utilizing LM317 and couple resistors setting voltage so that battery would be charged at recommended 13.2V. In order to prevent back supply a Shottky was used. Of course it adds some voltage drop (0.7V worst case). This was taken in account while calculating voltage adjust resistor divider. As a test [Alex] left solar charger for three days connected to his battery and it charged up to 12.35V which is about 75% of capacity. Not bad at all.

Have you seen RGB seven segment LED display?

Seven segment LED displays usually come in single color like red, green, blue or yellow. But probably there isn't any RGB displays in a market yet. After this mod situation can change.Markusdecided to fill this gap and made one by himself. All he did is took a an existing 7-segment display and removed single colored LEDs with dremel and replaced them with SMD RGB LEDs.

SMD LEDs already were with magnet wires that made the process easier. Obviously the number of pins tripled so additional socked was needed. He made a simple board with all pins and glued a display to it. Great inspirational work. isn't it?

Adapting graphical LCD with touch screen to ChipKIT UNO32

ChipKIT is a great substitution board to Arduino. It offers better performance as it is based on PIC32MX320F128 microcontroller based on 32-bit architecture. Microcontroller has 128K of Flash and 16K of SRAM on board. Having Arduino Uno shape factor ChipKIT offers more 42 programmable pins.

ChipKIT like Arduino can be programmed with bootloader that communicates to PC through USB-to-USART converter chip FT232RQ. Digilent has developed an STK500v2 based bootloader that works on PIC so it is easy to program using AVRDUDE tool. Besides that they adapted an Arduino envoronemt to work with ChipKIT boards. It's called Mpide. It also support Arduino boards but it aim is to program ChipKIT boards. Progamming experience is pretty same as for Arduino and even most of examples written for Arduino works on ChipKIT. This is true since there is no specific hardware elements touched like program memory or EEPROM. As you know Arduino is rich in hardware support libraries as all shields are designed for arduino. Late comers like ChipKIT even if they are hardware compatible may have some difficulties with library integration due to different architecture.

But with little bit effort you can make everything work.

Today I am going to try to run ITDB02 LCD module shield from iteadstudio.com.

IT is basically an adapter for graphical color LCD with touchscreen/SD. Note! Touch screen and SC cannot work simultaneously due to shortage of pins. Anyway a little hack on ChipKIT would solve this problem. Lets see what is a starting point.Henning Karlsenhas nice written libraries for Arduino and even for ChipKIT. But this library won't work with ITDB02 shield as decided not to support this shield due to performance loss. Also he claims that this shield is not optimized for 3.3V power supply as there are resistors included. Instead he offers to make custom cable for interfacing LCD or use another shield for ChipKIT. I understand that move. If we look at ChipKIT pin layout we can clearly see that Arduino compatible pins aren't bit aligned as it is in Arduino:

In Arduino digital pins D7..D0 are all PORTD pins. So they can controlled with PORTD command that gives significant increase of performance comparing to individual digitalwrite() commands. ChipKIT as you can see have these pins scattered and cannot be controlled with port commands. Instead you can see inner pins of header being aligned [RE0..RE7]. This is why another shield is offered that allow controlling LCD data pins with single command. Anyway I already have my ITDB02 shield on my table and want to make it work on ChipKIT. As starting point I've chosen to muck around with Arduino library due to same pin connectivity.

The main problem with controlling LCD that we cannot use port commands here as port pins aren't aligned. To solve this I have written simple function that takes data byte and scatters them to d0..d7 pins according to layout:

void ITDB02::byteD0D7(unsigned char data)
{
  //ChipKIT pins DR9|RD2|RD1|RF1|RD0|RD8|RF3|RF2
  if((data)&(0b10000000)) digitalWrite(7, HIGH);
    else digitalWrite(7, LOW);
  if((data)&(0b01000000)) digitalWrite(6, HIGH);
    else digitalWrite(6, LOW);
  if((data)&(0b00100000)) digitalWrite(5, HIGH);
    else digitalWrite(5, LOW);
  if((data)&(0b00010000)) digitalWrite(4, HIGH);
    else digitalWrite(4, LOW);
  if((data)&(0b00001000)) digitalWrite(3, HIGH);
    else digitalWrite(3, LOW);
  if((data)&(0b00000100)) digitalWrite(2, HIGH);
    else digitalWrite(2, LOW);
  if((data)&(0b00000010)) digitalWrite(1, HIGH);
    else digitalWrite(1, LOW);
  if((data)&(0b00000001)) digitalWrite(0, HIGH);
    else digitalWrite(0, LOW);
}

This is the bottleneck of performance as each individual pin has to be set individually (read modify write operation), while in Arduino there were PORTD = VH; Anyway this workaround works. Also I've changed control pin manipulation with digitalWrite() commands. And surely as as all font/image arrays are stored in SRAM there is no need for pgm_read_byte() commands. Simply we replaced with array read statements.

Arduino based Touchscreen library works on ChipKIT out of box, so no modifications are needed.
Here are few images of working LCD:

Next logical step would be to adapt library for SD card. But this will be next time.

Reverse Polarity Protector

A series diode is often used as a means of protecting equipment from accidental power supply reversal, particularly in battery-powered equipment. Due to forward voltage losses, this is sometimes impractical. One solution is to use an enhancement mode P-channel power Mosfet (Q1) in series with the positive supply rail. A device with low drain-source "on" resistance can be selected to minimise voltage losses, which in turn extends battery life and reduces heat dissipation.

Circuit diagram:

Reverse Polarity Protector Circuit Diagram

Zener diode ZD1 must be included to protect against excessive gate-source voltage, while a 100kΩ resistor limits zener fault current. A second 100kΩ resistor across the output ensures that the gate doesn’t float when the input is disconnected. A series fuse and bidirectional transient voltage suppressor (TVS1) could be included to provide over-voltage protection, if desired. If common input & output grounds are unimportant, then a version of this circuit employing an N-channel power Mosfet in series with the negative (0V) rail could also be employed.
2N2222A PDF   MUR860 PDF DB107 PDF TOP224Y PDF K2611 PDF

Low-Cost Dual Power Supply

This circuit shows how to symmetrically split a supply voltage using a minimum of parts - one LM380 power amplifier plus two 10μF capacitors. It was originally published in National Semiconductor's AN69 and provides more output power than a conventional general-purpose op amp split power supply. Unlike the normal power zener diode technique, the LM380 circuit does not require a high standby current to maintain regulation. In addition, with a 20V input voltage (ie, for ± 10V outputs), the circuit exhibits a change in output voltage of only about 2% per 100mA of unbalanced load change. Any balanced load change will reflect only the regulation of the source voltage, Vin.

Circuit diagram:

Low-Cost Dual Power Supply Circuit Diagram

The theoretical plus and minus output tracking ability is 100% since the device will provide an output voltage at one-half of the instantaneous supply voltage in the absence of a capacitor on the bypass terminal. The actual error in tracking will be directly proportional to the unbalance in the quiescent output voltage. An optional 1MO potentiometer may be installed with its wiper connected to pin 1 of the LM380 IC to null any output offset. The unbalanced current output is limited by the power dissipation of the package.

In the case of sustained unbalanced excess loads, the device will go into thermal limiting as the internal temperature sensing circuit begins to function. And for instantaneous high current loads or short circuits, the device limits the output current to approximately 1.3A until thermal shutdown takes over or the fault is removed. For maximum output power (2.5W), all ground pins (3-5 & 10-12) should be soldered to a large copper area (the LM380 data sheet contains more details).
TB6560AHQ PDF  TL084CN PDF  74HC244 PDF  LM258 PDF  TIP142 PDF

Power MOSFET Bridge Rectifier

The losses in a bridge rectifier can easily become significant when low voltages are being rectified. The voltage drop across the bridge is a good 1.5 V, which is a hefty 25% with an input voltage of 6V. The loss can be reduced by around 50% by using Schottky diodes, but it would naturally be even nicer to reduce it to practically zero. That’s possible with a synchronous rectifier. What that means is using an active switching system instead of a ‘passive’ bridge rectifier.

The principle is simple: whenever the instantaneous value of the input AC voltage is greater than the rectified output voltage, a MOSFET is switched on to allow current to flow from the input to the output. As we want to have a full-wave rectifier, we need four FETs instead of four diodes, just as in a bridge rectifier. R1–R4 form a voltage divider for the rectified voltage, and R5–R8 do the same for the AC input voltage. As soon as the input voltage is a bit higher than the rectified voltage, IC1d switches on MOSFET T3.

Just as in a normal bridge rectifier, the MOSFET diagonally opposite T3 must also be switched on at the same time. That’s taken care of by IC1b. The polarity of the AC voltage is reversed during the next half-wave, so IC1c and IC1a switch on T4 and T1, respectively. As you can see, the voltage dividers are not fully symmetrical. The input voltage is reduced slightly to cause a slight delay in switching on the FETs. That is better than switching them on too soon, which would increase the losses.

Circuit diagram:

Power MOSFET Bridge Rectifier Circuit Diagram

Be sure to use 1% resistors for the dividers, or (if you can get them) even 0.1% resistors. The control circuit around the TL084 is powered from the rectified voltage, so an auxiliary supply is not necessary. Naturally, that raises the question of how that can work. At the beginning, there won’t be any voltage, so the rectifier won’t work and there never will be any voltage... Fortunately, we have a bit of luck here. Due to their internal structures, all FETs have internal diodes, which are shown in dashed outline here for clarity.

They allow the circuit to start up (with losses). There’s not much that has to be said about the choice of FETs – it’s not critical. You can use whatever you can put your hands on, but bear in mind that the loss depends on the internal resistance. Nowadays, a value of 20 to 50 mW is quite common. Such FETs can handle currents on the order of 50 A. That sounds like a lot, but an average current of 5 A can easily result in peak currents of 50 A in the FETs.

The IRFZ48N (55 V @ 64 A, 16 mW) specified by the author is no longer made, but you might still be able to buy it, or you can use a different type. For instance, the IRF4905 can handle 55 V @ 74 A and has an internal resistance of 20 mR. At voltages above 6 V, it is recommended to increase the value of the 8.2-kR resistors, for example to 15 kR for 9V or 22 kR for 12 V.
Source: http://www.hqew.net/circuit-diagram/Power-MOSFET-Bridge-Rectifier_12743.html

Adjustable Current Limit For Dual Power Supply

This current-limiting circuit, shown in this example as part of a small bench power supply, could in principle be used in conjunction with any dual-rail current source. The part of the circuit to the left of the diagram limits the current at the input to the dual voltage regulator (IC4 to IC7) so that it is safely protected against overload. The circuit shown produces outputs at ±15 V and ±5V. The voltage regulators at the outputs (7815/7805 and 7915/7905) need no further comment; but the current-limiting circuit itself, built around an LM317 and an LM337, is not quite so self-explanatory.

The upper LM317 (IC1) manages the current limiting function for the upper branch of the circuit. The clever part is the combination of the two resistors R1 and R3 between the output and the adjust input of the regulator. In the basic LM317 configuration in current-limiting mode (i.e.,as a constant current source), just one resistor is used here, across which the regulator maintains a constant voltage of 1.25 V. The current is thus limited to a value of 1.25 V/R. To obtain a maximum current of 1 A, for example, the formula tells us that the necessary resistor value is 1.25R.

Unfortunately it is not practical to try to build an adjustable dual-rail current-limited supply in this way, as stereo potentiometers with a value of 1.2R are extremely difficult, if not impossible, to obtain. We can solve the problem using the technique of dividing the resistor into two resistors. Only the resistor at the output of the LM317 (R1) serves for current sensing. The second resistor (R3) causes an additional voltage drop depending on an additional (and adjustable) current. When the sum of the two voltages reaches 1.25 V current limiting cuts in.

Circuit diagram:

Adjustable Current Limit For Dual Power Supply Circuit Diagram

This makes it possible to adjust the current limit smoothly using the current in the second resistor (R3). This can be done simultaneously in the positive and negative branches of the circuit, as the diagram shows. It would of course be wasteful to arrange for the current flowing in the second resistor to be of the same order of magnitude as the current in the main resistor. We therefore make the value of the second resistor considerably greater than that of the main one. If the main resistor (R1) has a value of 1.2R (giving a maximum current of 1 A), and the second resistor (R3) a value of 120R, the necessary voltage drop is achieved using an extra current of 10 ent limit will be 1 A.
TIP142 TDA2003 L298N PIC12F508 74HC14
For the negative branch of the circuit the LM337, along with resistors R2 (1.2r) and R5 (120R), performs the same functions. A further LM317 (IC3) is used to set the overall current limit point by controlling the additional current. The resistance used with this voltage regulator, wired as a current sink (R4 in series with P1) determines the additional current and therefore also the output current in both the negative and positive branches of the circuit. Since we also want the total resistance of R4 and P1 to be 120R, we use a value of 22R for R4 and 100R for P1 to give a wide adjustment range for the output current from a few milliamps to 1A.

The minimum input voltage for the circuit depends on the desired output voltage and maximum output current. The input to the 7815 should be at least 18 V. We should allow approximately a further 1.2 V 2.2 V for the voltage drops across IC1 and R1. If we allow a total of 4V for the current limiting circuit in each branch, this means that the circuit as a whole should be supplied with at least ±22 V to produce well-regulated outputs at ±15 V and ±5V. If the symmetrical input voltage is to be provided using a single transformer winding, two diodes and two smoothing capacitors, it important to ensure that the capacitor values are sufficiently large, as there will be considerably more ripple than there would be with full-wave rectification.

Depending on the application, capacitors C6 to C9 at the outputs of the fixed voltage regulators can be electrolytics with a value of 4.7 μF or 10 μF. To improve stability, electrolytic capacitors can also be connected in parallel with C1, C2, C4 and C5.

How to show character on sevent segment display

Actually, seven segment possible show character like r,E,S,P,O,n,I.
I will explain how it can work. I used AT89C51 Microcontroller, this chip produce by ATMEL. With simple Assembly script, this project could be created. For coding and compiling use Systronix RAD51.
ASM Source Code

ORG 0H
MULAI: MOV A, P3
CJNE A,#0BFH,MULAI ;WAIT UNTIL BUTTON PRESS P3.6
JALAN:
MOV P1,#0CEH ;show r
ACALL DELAY
MOV P1,#86H ;show E
ACALL DELAY
MOV P1,#92H ;show S
ACALL DELAY
MOV P1,#8CH ;show P
ACALL DELAY
MOV P1,#0C0H ;show O
ACALL DELAY
MOV P1,#0C8H ;show n
ACALL DELAY
MOV P1,#92H ;show S
ACALL DELAY
MOV P1,#0F9H ;show I
ACALL DELAY

;
MOV A,P3 ;check if button P3.7
CJNE A,#7FH,JALAN ;if not go label jalan
MOV P1,#0FFH ;turn of all segment
SJMP MULAI ; goto? label mulai
;
;-------------------------------
; sub rutin delay
;-------------------------------

DELAY:
MOV R0,#5H
DELAY1:
MOV R1,#0FFH
DELAY2:
MOV R2,#0H
DJNZ R1,$
DJNZ R1,DELAY2
DJNZ R0,DELAY1
RET
;
END
asm source
hex file
Copyright and Credits:
Writer, ? puguhwah, graphics and photos, May2011.
http://www.hqew.net/circuit-diagram/How-to-show-character-on-sevent-segment-display_13067.html

How to show character on sevent segment display

Actually, seven segment possible show character like r,E,S,P,O,n,I.
I will explain how it can work. I used AT89C51 Microcontroller, this chip produce by ATMEL. With simple Assembly script, this project could be created. For coding and compiling use Systronix RAD51.
ASM Source Code

ORG 0H
MULAI: MOV A, P3
CJNE A,#0BFH,MULAI ;WAIT UNTIL BUTTON PRESS P3.6
JALAN:
MOV P1,#0CEH ;show r
ACALL DELAY
MOV P1,#86H ;show E
ACALL DELAY
MOV P1,#92H ;show S
ACALL DELAY
MOV P1,#8CH ;show P
ACALL DELAY
MOV P1,#0C0H ;show O
ACALL DELAY
MOV P1,#0C8H ;show n
ACALL DELAY
MOV P1,#92H ;show S
ACALL DELAY
MOV P1,#0F9H ;show I
ACALL DELAY

;
MOV A,P3 ;check if button P3.7
CJNE A,#7FH,JALAN ;if not go label jalan
MOV P1,#0FFH ;turn of all segment
SJMP MULAI ; goto? label mulai
;
;-------------------------------
; sub rutin delay
;-------------------------------

DELAY:
MOV R0,#5H
DELAY1:
MOV R1,#0FFH
DELAY2:
MOV R2,#0H
DJNZ R1,$
DJNZ R1,DELAY2
DJNZ R0,DELAY1
RET
;
END
asm source
hex file
Copyright and Credits:
Writer, ? puguhwah, graphics and photos, May2011.
http://www.hqew.net/circuit-diagram/How-to-show-character-on-sevent-segment-display_13067.html

Piezoelectric Triggered Switch

Two different switch circuits are shown.  One sources current and the second sinks current.  Both switches are connected to a piezoelectric wafer.  When the wafer is tapped, the switches are activated. 

 

Computer Power Supply Circuit

Computer Power Supply Circuit

“Computer Power Supply Circuit”

Even power device is made to provide energy to some pc. It really is usually devised for converting alternating electric current, (AC), in order to low attention household power, (DC). Without having this bit of equipment, the pc is simply package of metallic and plastic material. Pc power models are ranked on the optimum output energy.

Computer Power Supply Circuit

The ability provide ought to be the wattage recommended for your requirements from the pc, such as the optionally available elements. Utilizing a higher power ranking than needed would be a waste associated with electrical power, along with becoming less effective. As well lightly packed and also the pc will never functionality correctly, and could turn off. Generally there aren’t numerous computers which necessitate a lot more than 300-350 w, optimum.
The actual exceptions tend to be servers as well as gaming devices with several high energy (GPU) visual processing models. The actual GPU is really a solitary chip processor chip, such as the PROCESSOR, that is the actual central running device. The actual GPU assists the PROCESSOR run softer and much more effectively if you take more than functions for example THREE DIMENSIONAL motion as well as illumination. Movie cards as well as hd press has resulted in energy demand in certain computer systems in order to 400-500 w.

Computer Power Supply Circuit

TIP142 Circuit  TDA2003 Circuit  L298N Circuit  PIC12F508 Circuit  74HC14 Circuit   IRF840 Circuit

PCB Printed Circuit Board

PCB Printed Circuit Board

“PCB Printed Circuit Board”

Your current often see PCB described across the net in addition to different trade publications and think to oneself that you simply observe this composition mentioned are usually never ever quite positive what is needed.
Plenty of better technology wasn’t able to are present with out a PCB set up. Generally, any PCB is actually a aspect manufactured from many layers regarding insulating substance along with power conductors. Frequently, the particular insulator is constructed of many different types of substance that may usually be according to fibreglass, plastic-type or perhaps ceramics. Each time a PCB is established, the particular manufacturing method really etch off different chapters of the particular PCB so that you can depart one accomplished printed routine board you can use by having an digital aspect.
The regular common to get a PCB today, no matter the several types of supplies is anything called a PIC2221A. It is not important is actually a PCB will be double sided, individual sided or perhaps several different tiers, the typical remains found in the particular manufacturing method. To get a special type of oral appliance regarding technological innovation, designer can make proper sectional specifications from your IPC2220 sequence. In the event the artist is using strength conversion products, then a further parameters are usually recommended from the IPC9592.
From this article you can see, there are several versions of your PCB, and perhaps they are only a few since easy because you can consider. And so the the very next time you choose the TV SET distant, have a very take into account the different manufacturing functions the PCB might have experienced ahead of the ultimate product has been placed within just your distant.

How Much Does an OCx Circuit Cost?

Cost Circuit

Cost Circuit

You ask for a general explanation of bandwidth cost and the factors impacting it. The best place to look is in your own question — you have already covered most of the factors!
Bandwidth is generally billed at either a flat rate (1.54 megabits/second for a whole month), or at a per-unit rate ($1.00 per gigabyte). The units can be measured over a period of time, or can be peak units. Each bandwidth provider has their own methods of accounting and billing.
Factors that can raise (or lower) the cost of bandwidth includethe volume needed – obviously Yahoo and Google are going to get a better cost per unit than you or I would. They also include the quality of service — a 99.99999 guaranteed uptime on the connection with multiple upstream providers and hot failover protection is a lot more costly than a simple T-1 from the local RBOC.
Additionally, location is going to have a lot to do with bandwidth charges. In a major metropolitan area with many bandwidth providers, the costs are going to be lower because of competition and exiting infrastructure. However, in rural Kansas, getting high bandwidth to the ranch will cost a significant amount more, simply because there are very few providers, and the line charges (especially if a new line has to be run!) are more. Less competition = higher costs. Less infrastructure = higher costs.
To address the core of your question, how cheap can *you* get it, I would need to know a lot more about your situation: Where are you? What do you want to do with the bandwidth? How much do you need? What level of service do you need? Could you be better served by colocating your hosts somewhere, and taking advantage of their bandwidth?
For example, if you have an office that needs internet connectivity for mail and light web browsing, a simple business DSL line for less than $100 a month would suit you well. However, if you are an adult video producer that wants to deliver all the video content over the web, you would be well suited to colocating your product with a major firm on one of the backbone lines in California or New York. You could still expect to see charges in excess of $5,000 a month.
In summary, location is the main factor in determining the prices of OCx circuits. It’s best to contact a service provider of these large circuits to determine the specific needs of your business, which will then give you a more accurate OCx price quote.
http://www.hqew.net/circuit-diagram/How-Much-Does-an-OCx-Circuit-Cost$3f_12838.html

Digital Logic Circuit Design simulator Software

Date: 2012-11-12Author: anonymousReading(36)Collection this page

MultiMedia Logic Digital Circuit Design simulator Download

This multimedia logic simulator software is simplest, most powerful, most universal languages known (Digital Logic).? Most digital logic drawing systems are just that, drawing systems.? Recently, some logic drawing systems allow circuits to be activated as they are drawn for testing purposes.? But the input and output to these systems are typically files of numbers.? The MultiMedia Logic Simulator has taken this one step further and introduced devices that connect directly to your computers’ real devices (e.g. Keyboard, Screen, Serial Ports) including MultiMedia ones (PC speaker, Wave, Bitmaps).
The intent of this system is not to necessarily build the logic circuit you design.? The intent is to use what you build, to allow experimentation, to learn and to have fun.
This Complete installation kit for all 32-Bit Windows. (NT/2K/Xp/95/98/ME, VISTA, Windows 7)

Download

Please send your ideas, which are very important for our success…

Power Amplifier Speaker Protection Circuit Schematic

While switching a power amplifier on, a loud thump sound is heard to sudden heavy discharge current through the speaker at the time of power on. This current may damage the speaker, especially in case of direct coupled amplifier.

PARTS LIST
R1	5KΩ Preset
C1	1000μF 25V
C2	0.1μF (104)
D1	IN4001
Q1	BC107
RL1	9V 500Ω Relay
LS1	Speaker

The circuit given here protects speakers from the current surge. When the amplifier is off, relay switch is also off. When the amplifier is switch on, R1 and Ci provide delay of a few seconds to switch the transistor on which energizes the relay.

Power amplifier 100w vmosfet 1

 One still designing that it uses in the exit transistor of technology V-mosfet. This transistors to us offer a lot of virtues concerning the simple bipolar transistors, as high speeds, thermic stability, low distortion etc. Beyond this circuit use also other useful solutions as use fet as source of current [ Q3 ], trimmer TR1 with which we match the characteristics of differential amplifier of entry Q1-2. Also extensive is the use of sources of current wilson Q7-8 and Q10-11. With trimmer TR2 regulate the bias current of output stage, in the 100 ma. The use of diodes D2 until D5 in combination with the resistances R17-19, they protect the gates of transistors v-fet from exceeds the voltage ? 14V and it creates perforation in very thin layer SiO2, that is used as insulation in the gate. This way of protection is common in all the amplifiers that use these transistors. The total gain of amplifier is 32.6, regulated from the R18, R6 and R8, in the negative feedback. Also is used enough the use of local feedback for stabilisation of operation under all the conditions. Because the transistors v-fet have positive factor of temperature, with result with the increase of temperature is increased also their resistance. This increase has as result the reduction of current that via the transistor, hence also his power. The use of separated supply in the stages of drive and exit, ensures stability and reject of distortion of intermodulation. The initial drawing of is L. Hood and was published by the Wireless Word.

Bridge converter

This is a very useful circuit for those who want to transform a stereo Power Amplifier, to mono, bridging  two channels from him , reversing the phase of the one power amplifier [R] and the polarity, with  these connections we can have 4X times the output power (double the output voltage ) . For example : if we use the circuit to a stereo amplifier 2X50W, will have 1X200W output , if power supply assent.

How to Work?

the connector J1, we can connect two type plugs (XLR) Cannon, and input of two channels it's symmetric (electronic balance). With potesometer VR1 and VR2, we regulate the level of each channel separately (stereo), switch S1a-b [place 2]. When bridging two amplifiers, with the switch S1a-b [place 1], then the level him we regulate only with the VR1. The department of channel [ R ] is suppressed and the input is given only in [ L ] channel. Simultaneously inputs in use the inversion department of phase round the IC1c, driving second power amp. [ R ], with reverse polarity, from [ L ] channel. The output now it should him we take from two [ ] positive output final amplifiers. In the circuit it appears association the loudspeakers and for the two cases (stereo - bridge). In order to we have results of precision, should the resistances of input differential amplifiers, be metal film 1%, pontesometer, the capacitors and switch S1, good quality. The power supply of circuit is ? 15V, stabilised. If you want to use the inputs, no as symmetrical (balance), but as asymmetrical (unbalance), you can connect in 0V, the negative inputs of signal J1/1 [L/mono] and J1/5[R ]. The asymmetrical signal now enters in the positive inputs, J1/2 and J1/6.

ATMEGA8 Circuit RTL8201CP Circuit AT89C51 Circuit PCF8563 CircuitIn

Flashing STM32 using J-Flash ARM

Last time we have covered topic about flashing STM32 microcontrollers using bootlaoder. This is easiest and cheapest way of loading programs to MCU memory. But this isn’t the only way of doing this. Software can also be downloaded to using JTAG adapter which is used for debugging. This time we are not digging into debugging but staying only with programming.

You can download latest J-Link software from Segger Download page.You will be asked for adapter serial number which can be found on back side of J-Link adapter. Once installed you will get a bunch of programs used for various purposes. We are going to use J-Flash ARM which is used for programming microcontrollers using J-Link Adapter. J-Flash ARM is a GUI interface that allows easy work with ARM microcontrollers. It supports most of ARM microcontrollers including ARM7/9/11 and Cortex-M0/M3. Programming speed reaches up to 150kB/s.

Lets start J-Flash ARM to give it a try.

This is main window where you can see project details, Flash contents to be uploaded and LOG messages. If you have already connected your J-Link adapter to ARM board you can load compiled binary in any popular format like .hex, bin, etc.

Source: http://www.hqew.net/circuit-diagram/Flashing-STM32-using-J$2dFlash-ARM_13456.html

Flashing programs to STM32. Embedded Bootloader

There has been several requests among users to explain more about loading programs in to flash memory of STM32 microcontrollers.

This of course is a wide topic but lets focus on how to achieve result – flash program in to MCU. Depending on what arsenal is on your desk you can do in several different ways. Let’s try to go through them in practical way.

Embedded bootloader

All STM32 microcontrollers comes with built-in bootloaders that are programmed during production. Depending on device type flash memory can be programmed using one of interfaces like USART1 or USART2, USB, CAN. Mostly we are dealing with low, medium and high density devices so they can access bootloader using USART1 interface. USART1 can be connected to computer using RS232 interface or USART to USB driver chip like FT232. In order to enter bootloader special MCU pins has to be set to proper logical values. These are called BOOT0 and BOOT1 pins on a microcontroller. Boot pins can have several cases:

As you can see there are three cases: first case is when BOOT0 pin is tied to ground and BOOT1 is open or at logical state 0 then after reset program is executed from Main Flash Memory. This is your normal configuration when executing programs. Second case (BOOT1=0; BOOT0=1) means that after reset execution starts at System memory where built int bootloader resides. This is the case when we need to upload binaries via USART1. And third case means that program execution is performed in SRAM. So lets focus on second case – System memory. In many development boards you will find jumper pins where you can select BOOT0 and BOOT1 configurations. For instance in STM32F103RBT6 board these looks like this:

In image you can see that jumper settings already selects to run internal bootloader. What we do next is download Flash Loader Demonstrator which is a tool to interact with bootloader. Install it and launch. You will see screen where you will be able to select USART parameters. Be sure to select correct COM port:

Read more at http://www.hqew.net/circuit-diagram/Flashing-programs-to-STM32$2e-Embedded-Bootloader_13458.html

speech filter

The human speech apprehend a small area of frequencies, that is extended from 300HZ until 3KHZ. This spectrum is also internationally recognized for the transmission of speech via telecommunications networks. This is also the mainer use of this circuit, one and it can be used in uses that we needed this concrete spectrum of frequencies, rejecting the spectrum on and under what, making comprehensible the speech. The circuit is constituted by two active units, filters of second class (calculated for critical damping). The first filter round the IC1A rejects the low frequencies (under 300 HZ) [high pass] and the second IC1B high (above 3KHZ) [low pass], composing thus a total filter band pass of area (300HZ-3kHZ). In order to has good yield the filter, as with all the filters, it should are used resistances metal film 1% and capacitors polysteryne.

3 Way Active Loudspeaker gr

Fig.5--Crossover calculation

Source: http://www.hqew.net/circuit-diagram/3-Way-Active-Loudspeaker-gr_13464.html

6V6 6J5 Class A Vacuum Tube (Valve) Amplifier Circuit

This is my first successful vacuum tube project.? The output of this small amplifier in which a 6V6GT output pentode is connected as triode is about 4.5 watts.

This project involves a single ended audio amplifier, which consists of a resistive input network, a driver stage, and an output stage to a typical 8 ohm loudspeaker load, all the while, using a minimum of supportive passive components for biasing and coupling duties. Power-supply voltage is provided by? full wave diode rectification of 230 VAC by a magnetic transformer. This design provides a quality audio amplifier.

Valve amplifier circuit diagram

CD4060 Timer Circuit 1 minute to 2 hours

CD4060 Timer Circuit 1 minute to 2 hours

This is a 1 minute to two-hour timer switch. The 14-stage binary ripple counter Type 4060, IC1, has an on-chip oscillator capable of stable operation over a relatively wide frequency range. In the present circuit, the oscillator frequency is determined by an external RC network connected to pins 9, 10 and 11.

PARTS LIST
R1	2.2MΩ
R2	18KΩ
R3	1KΩ
R4	1KΩ
R5	1KΩ
R6	1MΩ
VR1	500KΩ (504)
C1	220nF (224)
C2	10nF (103)
D1	LED
D2	LED
D3	1N4001
Q1	BC547
IC1	CD4060
RL1	Relay

When the power is on, the pulse at junction R6-C2 resets the counter and counting starts. When the counter reaches bit 14 (Q13), pin 3 goes high so that the relay, a 9V type, is turned on via driver Q1.

CD4060 IC PINOUT

The time delay is set with the aid of VR1. Time delays of between one minute and two hours are possible by appropriate dimensioning of the timing components:

1-30 minutes: C1 = 220nF ; VR1 = 500KΩ.
1-60 minutes: C1 = 470nF ; VR1 = 500KΩ.
1-120 minutes: C1 = 470nF ; VR1 = 1MΩ.

The timer is powered by a 9V PP3 battery. Light-emitting diode D1 does not affect the operation of the circuit and is included merely to show that the timer works. Diode D1 and resistor R4 are , therefore, optional components.

Using SVN for embedded projects. Part 1.

Writing software is complex task. In every microcontroller program you usually try to reuse previously written libraries, downloaded code and other data that is being updated. What if you are developing something in team? How to keep track of everything? Storing project files in directories eventually get messy – eventually you loose track of whats done. For instance some time you have written LCD library and used in several microcontroller projects. But eventually you found a bug, or optimized code. Normally you would have to copy new library files in every project to keep updated. This is hard when you already have dozens of projects. There is one way to stay organized by using version control software. In this case we will talk about SVN.

Subversion (SVN) is an open source system that allows controlling files and folders, keep track of changes made during time. Simply speaking SVN is a virtual file system that keeps track of every change in files, directories. It’s a smart way of storing project files either you are working alone or in team. Using this system smart you will always have things organized and never loose version of your files gain.

TortoiseSVN your repository tool

TortoiseSVN is popular tool to work with SVN system. You can download it from project site here. We won’t be discussing on how to install it on your machine as it is well described in documentation you can download here. So Assume you already downloaded installed one that fits to your operating system. For instance if you have 64-bit Windows – downloadTortoiseSVN-1.7.10.23359-x64-svn-1.7.7.msior later release if its already there. After installation click right mouse button on any folder and you should see new menu items:

This means that installation went smooth and you can continue further. Before we begin there are couple terms to be remembered. Repository andworking copy (WC).

Repositoryis a SVN itself where file structure is stored. It also keeps all changes since project creation. Every change is assigned with revision number to keep track. Each revision can be accessed ans used when needed. Changes cannot be made inside repository for this a local working copy is used. All changes are made here and then they are fixed in repository with new revision number.

AVR DDS3 boards have arrived

Finally some update on AVR DDS3 signal generator. Circuit is practically done and PCBs are made. I decided to go with two microcontrollers on board to make it more functional. One microcontroller Atmega328P is gonna be dedicated to user interface and signal generator control. Second Atmega88 is gonna be used for signal generator only. This will give un-interruptable signal output while changing parameters or simply doing signal sweeps.

Simple keypad should be convenient for entering frequency values and menu navigation.

Maybe this isn’t best choice but this is what I had on a desk and wanted to put in to use. If I find it annoying and there will be more bugs or more flaws schematic will be remade.

Decided to add computer interface. So there is an UART connector that suits SparkFuns FTDI Basic Breakout board.