This circuit was found in a 90’s Popular Electronics. The power transistors must be equipped with radiators and the transformer has a 2 to 5 A secondary.
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...