This circuit was found in Motorola documentation from 1966. The lamps are according to power and current according to the components used which are uncommon today.
This circuit was found in an American 1980s documentation. PUTs are rare today. Capacitors C1 and C2 are...
Found in a Popular Electronics from the 80s, this circuit is intended to indicate the presence of...
This circuit was found in an old Poptronics but is still current as transistors can be replaced...