This LM380-based circuit was found in documentation from the 1980s. The components are current, and the transistor may be a general-purpose equivalent. Note the use of a medium impedance speaker.
To be used in greenhouses, heating or drying systems, this device activates a relay when the...
We found this transistorized circuit in a 1985 documentation. The circuit can operate with...
Found in Electronics Now from the 1980s, this amplifier can also be seen in commercial amplifiers...