This setting applies to virtually any photo transistor and any operational amplifier. The power supply must be symmetrical, and the gain is determined by the relationship between R2 and R1.
This circuit controls a heating element with voltage from 6 to 30 V and current up to 3 A from...
Indicated to operate in tube circuits, this preamplifier has 250 V power supply. The circuit is...
We found this circuit loader in a French magazine Electronique Radio Plans from July 1993. The...