This circuit for heating elements was taken from a 1966 General Electric manual. The SCRs are load-according, and the sensor is 1 ohm.
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The integrated circuit of this amplifier is not very common today. The output transistors can be...
Found in an old documentation about neon lamps, this circuit has the frequency basically...