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.

Transformer with DC

Circuit Description:

An ideal transformer (with sufficiently large inductance and sufficiently low resistance) can pass DC, but real transformers are not ideal and only work with AC. This transformer passes DC at first, but after a short time, the DC voltage fades due to resistance in the primary and the finite inductance of the transformer coils.