Found in a 1964 Electronic Design, this circuit uses a common LDR and transistors from that time. The relay is a high sensitivity type.
In this circuit the gain decreases as the input signal intensity increases. The circuit is from a...
This circuit was found in an American 1980s documentation. Dual FETs can be replaced by single...
September 2016 - Mouser Electgronics already has in stock the new moisture digital sensor HDC1010...