This circuit was found in a 1991 publication. The transistor can be a general-purpose type.
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....