This circuit was found in old American documentation. The operational amplifiers are from the period, but modern equivalents can be used.
This high-gain amplifier was found in the March 1994 issue of Electronics Now magazine. The...
Here is an interesting project for those who own a pool and are afraid that someone will fall into...
The sensor of this circuit is a common diode, and the measured range is from -10 to + 40º C. The...