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 1988 documentation circuit includes a charger and an inverter to power a small fluorescent lamp. The...
This circuit can act as a receiver for the transmitter of the previous circuit. We found it in...
The power source shown for powering for small TTL circuits was found on a Radio Electronics...