The purpose of this heat detector is to find hot spots on a board or other locations. The sensor is an integrated circuit from the period. The circuit is from Radio Electronics from May 1985.
This circuit uses two Raytheon RC4558 operational amplifiers that are similar to the 741. The...
This small stereo amplifier for headphones was found in a documentation on integrated circuits from...
This is a MOSFET version of a grid dip meter for frequencies between 1.8 MHz and 150 MHz,...