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 for the car was found in the April 1990 Radio Electronics magazine. The speaker is...
We found this circuit in a Texas Instruments documentation from 1973. Other operational amplifiers can...
This circuit was found in a 90's EDN. The circuit has a well-known configuration. The voltage...