We found these circuits in a 90s Radio Electronics. In them, we have the way to turn a load on and off using pressure switches. The circuit can be used with other types of direct current load.
This circuit allows you to use a calculator as a timer by directly activating a sum key with...
Found in American documentation from the 90s, this circuit has a timing system for activating the...
Found in an old American documentation this FM modulator makes use of a varactor diode. The...