This circuit with a bargraph scale was found in a 90s Popular Electronics. The circuit measures the intensity of a sound in three scales. R14 works as a sensitivity adjustment.
The frequency of the signal produced by this oscillator depends on the amount of light falling...
This circuit is from an Italian magazine Radio Elettronica of January 1977. The circuit shows how...
The circuit shown in the figure is intended for medical applications where the sector in contact...