This is the typical audio amplifier for a 1967 television. We found it in a magazine from the time. Note the use of the output transformer and the high supply voltage. The circuit is an RCA CTC21.
This circuit was found in an American documentation from the 90's. The circuit can use almost any...
This circuit triggers a relay when light strikes a sensor. The sensitivity is adjusted in the...
We found this circuit on the internet, but it has some problems. It will be convenient to limit the...