Suggested by a 1968 Motorola power semiconductor manual, this circuit uses a special transformer and transistors from the era. The frequency is 60 Hz.
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
We can use any type of resistive transducer with central resistance in the range of 10 k ohms to 1...
This circuit controls two lamps so that when one increases in brightness the other decreases. The...