We found this circuit in the March 1999 issue of Electronics Now magazine. The indicator used is an analog type. The values indicated depend on the calibration.
This circuit was found in a 1986 publication. However, it can still be easily assembled, as the...
In the figure we have an anti-ring circuit with 4093. The duration of the pulse is given by R1 and...
This circuit was originally indicated to generate audio signal for analog TV sound. The circuit is from...