This circuit with two operating modes was found in the September 1989 issue of Radio Electronics magazine. Other operational amplifiers can be used. The power supply must be dual.
This TTL circuit can be used as a shield, controlled by one of the inverters. The circuit must be...
This circuit, shown in the figure, consists of a variable gain amplifier with differential input...
We found this circuit in an Australian publication from 1991. It is a kit of the time with input...