We found this circuit in a 1971 documentation. The circuit can be assembled with more modern transistors such as BC548 for Q1, BC558 for Q2 and BD135 for Q3.
This is the receiver circuit for the transmitter of the previous circuit using an integrated...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...
We found this small audio amplifier in the November 1999 issue of Electronics Now magazine. The...