The circuit shown is from the 1977 GE semiconductor manual. More modern equivalent SCRs can be used. R1 must be wire type.
This circuit was found in a 1967 publication. Transistors can be modern general purpose. Component...
This circuit was found in an 80's Radio Electronics. The circuit multiplies the frequency of a low...
This flasher for power loads such as lamps and LEDs uses a 555 as an oscillator. The supply...