This circuit was found in the February 1980 issue of Radio Electronics magazine. The digital circuit was shown in two parts, using 20 LEDs in a configuration with the LM3914.
We found this circuit in a 1990 documentation. The operational amplifiers are type 741 and the LED is...
This circuit was found in a 1968’s publication and uses germanium transistors. Equivalents can be...
This 5 V circuit was found in December 1978 Radio Electronics magazine. The power transistor must...