The figure shows the equivalent circuit for the LM381 audio preamplifier IC. The circuit was found in the February 1990 issue of Radio Electronics magazine.
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
This circuit was found in old documentation. D1 can be a diac. | Clique na imagem para ampliar...
This oscillator takes advantage of the 2000 ohms headphone inductance as the oscillator circuit coil....