Thread: What is the most practical way to power operational amplifiers?

We've been learning about op-amp circuits, and in the lab we power them with a power supply that has a range of 0-20 V, with two sources so that both polarities are available (we generally use +/- 12 volts). Obviously, this isn't very practical for most applications. Is there a way to power op-amp circuits without having to use two 9 volt batteries or an expensive power supply?

You can use one power supply for both the plus and minus inputs. Run leads out of both the positive and negative inputs and put a 1k-ohm resistor on each. Feedback one polarity around one resistor so that it bypasses the resistor and goes right to the input. Check out how a common-mode voltage amplifier works.