This circuit amplifies signals from 0.5 Hz to 300 kHz. We found it in an old documentation. Equivalent transistors may be used. The gain is 20 dB.
This circuit is from Popular Electronics from the 90's. The circuit discharges the battery with a...
We found this time base circuit in a timer project from the August 1972 Radio Electronics...
This sonic switch, vox or sonic relay uses a Darlington of the time that has a gain of 10,000. The...