Found in American documentation from the 90s, this circuit triggers a buzzer with a Sonalert-type oscillator when the temperature of the sensor reaches a certain value set in R2.
This small signal injector generator was found in the February 1971 issue of Radio Electronics magazine....
This amplifier, found in a 1981 publication, provides 15 W lHF power with a supply voltage of 14.4...
This simple passage alarm is powered by the power grid using an LDR as a sensor. The circuit is...