Turning your Bench Supply intoa Dual Supply

When experimenting with opamp circuits, a dual supply is often needed. The circuit here presents a simple add-on that turns an ordinary bench power supply (PSU) into a dual supply.The circuit creates, electronically, a midpoint at U/2 which is used as the ground reference for the circuit under test. Basically, the add-on is a non-inverting opamp buffered with a couple of darlington power transistors. The buffering makes the add-on capable of delivering several hundred milliamps. Note that the phase reversal of the buffer circuit means that the feedback has to be returned to the non-inverting input of the CA3140.