Obtained in a 1968 Electronics World, this circuit uses transistors from the time and the sensor is a common LDR. The component values are for scales from 0.01 to 100 foot-candle.
Two tone siren (CB9085E) This circuit was found in a 1980’s Radio Electronics. The signal must be...
Found in an American publication from the 1980s, this circuit can be found in commercial sound...
We found this circuit in an 80's Radio Electronics. The circuit uses a PTC sensor and an LED...