This two-transistor circuit was found in the September 1971 issue of Radio Electronics magazine. The sensor is an NTC and sensitivity adjustment is via R1.
circuit is used to increase the sensivity of a relay. A 50 to 100 mA relay can be triggered with...
) We found this circuit in the November 1992 issue of Radio Electronics magazine. The 30V power...
These circuits use loads of 50 ohms to allow the use of a voltmeter in evaluating the output of a...