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.
This circuit was found in the component manual itself. The frequency can be changed and the power...
This crystal-controlled circuit was obtained from a 1980s documentation. The power supply should be 5...
The critical component of this amplifier is the output transformer. We found the circuit in an old...