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.
This circuit was obtained from an English documentation based on a 74121 TTL integrated circuit....
This circuit generates signals with opposite phases determined by C1 and adjusted by R2. The...
The presented circuit uses two old germanium transistors. We found this configuration in a...