This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is suitable for detecting explosions, distant echoes and seismic vibrations.
This circuit consists of a voltage regulator for 6 V batteries with a very low voltage drop. The...
This BFO or OFB for listening to SSB (Single Sideband) signals was found in the January 1996 issue...
We found this circuit in a European publication from the 1990s. Transistors are still common types...