This circuit is designed to analyze the distortion of an audio signal. We found it in an article in the October 1988 Radio Electronics magazine that teaches how to use it.
This circuit indicates when a 28 V lamp burns, lighting a neon lamp with higher voltage. The...
This circuit, which can be used on an optical link, is suggested by the Texas Instruments...
We found this circuit in a 1992 Popular Electronics. The circuit has an optical sensor with LED...