Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
The configuration shown in the figure uses two PNP transistors to activate the load when the input...
This amplifier with a few watts of power was found in a Japanese technical documentation from the...
This selective filter can be used with the previous receiver (CB19446E) in a simple remote-control system....