The purpose of this circuit is to reduce the ripple of a power supply. The circuit is from a Radio Electronics from March 1985. The transistor must have a capacitance according to the source.
We found this circuit in a 1977 publication for radio amateurs. It serves to test general purpose...
This circuit is from a 1998 Poptronics. The circuit triggers a buzzer after a certain time, waking...
This circuit for electronic voltmeter was found in a publication by Gernsback from 1960. The...