Using an LDR as a sensor, this circuit is from the Radio Electronics magazine of December 1984. The operational amplifier is the 741 and the source must be symmetrical.
In the 110 V network, capacitors of 200 V or more and in the 220 V network, capacitors of 400 V or...
The OC30 power transistor is an old type of germanium from the 60s. This amplifier, using this...
Found in Maxim documentation from the 90s, this circuit makes use of components from the period. The...