This circuit turns off a load after an interval of 8 to 80 seconds adjusted on the potentiometer. The circuit is from a Radio Electronics June 1970. The time depends on C1 and can be changed.
Using the LM3914, this circuit is suitable for benchtop experiments. It was found in the March 1995...
This very sensitive circuit works almost like an electroscope. The FET can be the BF245 and it...
This 50's receiver includes an amplifier stage with a transistor complementary to the CK722, in...