This circuit consists of a stereo audio compressor. We found it in Radio Electronics magazine from October 1968. The circuit uses an opto-coupler made with a neon lamp and LDR.
This circuit for link or alarm was found in the Encyclopedia of Electronic Circuits Volume 5 of...
This circuit is from a Popular Electronics of the 90's. Any power MOSFET can be used. The circuit...
This circuit extends the scale of a milliammeter. We found it in a documentation from the 60's. The...