Mini Megaphone (CB8952E)

Found in Popular Electronics' 90s, this small megaphone is based on LM386. The circuit uses a high impedance microphone.

Intermittent buzzer (CB20494E)
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...
Audio Oscillator (CB22250E)
This blocking oscillator was found in a publication from the 50's. The coils determine the...
20W amplifier per channel with the TPA3100D2 (Cb23591E)
The TPA3100D2 integrated circuit from Texas Instruments (www.ti.com) consists of an efficient...