This circuit is a four-quadrant multiplier using an LM3900. The circuit was found in the July 1988 Radio Electronics magazine.
The search coil of this detector consists of 140 turns of wire 18 in an 8 inch diameter form. The...
This circuit was obtained from a 1966 General Electric documentation. It can serve as a basis for...
The quiescent current of this alarm is in the order of microamps and the same is true for the...