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.
The oscillator in figure 1 can be used in alarm, call or warning systems, producing a sound of...
This circuit is from a 1973 documentation. In it we have the way of using a FET as an input of...
This circuit is for traditional old-style telephone lines found in an American 1980s...