This circuit is from an American documentation from 1975. The single junction transistors can be 2N2646 and the signal must be applied to the input of a good amplifier.
This circuit was found in a 1978 English magazine. It is a configuration that aims to select the...
This circuit was found in Maxim's documentation from the 90's. The circuit provides 12 V x 120 mA....
This circuit can be used as a shield. Its purpose is to detect the positive front of a signal...