This simple Bargraph photometer with 4 LEDs was found in a 1997 documentation. The scale is adjusted in a trimpot and the sensor can be any common LDR. Power can be supplied by cells or battery.
We found this sensitive moisture detector in an old documentation. The circuit uses a common JFET,...
This simple 2-transistor radio is from Radio Electronics in October 1952. The circuit outputs a...
This circuit was obtained in an American documentation of 1964. The transistors are of the time....