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.
By adding a transistor to the output and some polarization features we can obtain a higher output...
This circuit, from a 303 Circuits from the 90s, uses a telephone pickup coil as a sensor to...
Found in a manufacturer documentation from the 1980s, this circuit supplies currents that depend on...