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.
Line voltage compensation (CB8816E) This circuit for the alternating current line (AC line) was...
This circuit was obtained in a 1982 English magazine of 1982. This circuit has three external...
This circuit is based on the operational amplifier LM833 which is not a common component today. The...