Suggested by a 90s EDN, this circuit supports almost any LED as a source and a phototransistor as a detector. The circuit operates with a PLL 567 at a frequency of around 40 kHz.
The circuit shown is from Motorola's Linear Interface ICs from 1992. The circuit uses a...
This nice function generator circuit with the XR2206 was found in the May 1977 Radio Electronics...
This voltage inverter allows you to raise the voltage of a battery to values as high as 140 V...