This circuit is from a 1969 Electronics World. It generates 100 kHz sinusoidal signals determined by the crystal. Capacitors must be ceramic.
Only one LED is turned on when S1 and S2 are pressed. The LED that will be on is just the...
This circuit was found in a 90s Radio Electronics. The FM encoder or multiplexer is an uncommon...
This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A....