In the figure we have a simple way to have a peak bargraph indicator. The amplifier is of the audio type, but operational ones can be used. The circuit is from Radio Electronics from March 1980.
The presence of a low resistance between the terminals of the sensor causes this modulated...
The frequency of this oscillator depends on R and C (see math section for electronics). The...
This circuit was found in a 1980s documentation from the manufacturer of the integrated. The...