This circuit of the 80s makes use of an operational one of the time. It can be designed with modern operationals and must use a symmetrical power supply.
This circuit was found in an old documentation from Europe. The integrated circuit used is...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This photometer is based on a Wheatstone bridge that must be balanced by the linear potentiometer P1. The...