This circuit is from the 80's, using an integrated of the time. The circuit serves as a reference, as this type of dialing is no longer used today.
This logarithmic operational amplifier was found in the September 1994 issue of Electronics Now...
Indicated as a joke or challenge this circuit shows how it is possible to control two lamps using...
Found in a Linear Technology 80s integrated circuit manual this circuit has its gain controlled from...