This circuit is a four-quadrant multiplier using an LM3900. The circuit was found in the July 1988 Radio Electronics magazine.
The component used in this circuit is uncommon today, as the circuit was obtained from Motorola's Linear...
This simulated circuit on the NI Multisim transmits modulated infrared signals with the audio...
This voltage sensor limits the discharge of a Nicad battery. We found it in an American...