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 uses a Hall device from that time as a sensor. The circuit is from an English...
Found in Radio Electronics from the 90s, this siren finds many variations on this site. The...
This audio generator that produces both rectangular and sinusoidal signals was found in a...