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.
The purpose of this project is to monitor remote loads. The windings are made in a burnt...
The scale of this scale uses LEDs, and its accuracy depends on the number of LEDs. We found this...
We find this circuit in an American documentation from the 80's. The circuit has the coil given by the...