We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994. The circuit can be adapted to use other operational amplifiers and the power supply must be symmetrical.
Two sensors are used in this simple remote-control circuit, one to switch on and one to switch off the...
Using old germanium transistors like the CK722, this circuit has good gain. We found it in a...
We found this configuration in a 1974 publication. Transistors can be replaced with equivalents such as...