This circuit with different colored indicator LEDs has an expanded scale. We found it in the March 1992 Radio Electronics magazine. For an adjustable range of 0 to 10.5 V.
This circuit appears in similar versions on this site. This is from a Popular Electronics from the 80's. The...
This two-transistor delay circuit from the 1960s was found in documentation from the time....
This circuit operates with signals from 150 kHz to 1 MHz and makes use of a known NAND CMOS gate....