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.
This circuit generates sinusoidal and cosine signals of 2 kHz given basically by the values of C1...
This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that...
This circuit has both frequency and duty cycle control. We found it in the October 1992 Radio...