This circuit was found in a 1966 EEE. The circuit uses transistors from the time but can be made with modern equivalents. The operating frequency ranges from 0.1 to 1 kHz.
The purpose of this circuit is to turn off the power supplied by a battery when its voltage drops...
Found in National Semiconductor documentation from the 1990s, this circuit has a 10 kHz pass band...
Found in a 1980s documentation, this amplifier uses an integrated circuit of the era. The RLC...