This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response of 150 Hz to 40 kHz. The power supply must be symmetrical.
This 12V battery charging circuit automatically shuts off at the end of the charge. The disconnect...
This circuit was found in an 80's Electronic Design. The frequency depends on the crystal and the...
This circuit uses a metal enclosed transistor as a temperature sensor. The circuit is from an old...