Understanding VRef

[cranzor]

Hi everyone,

I've recently been playing around with circuits on a breadboard and as I wade a little deeper I'm starting to come across VRef but I'm not completely understanding what it is or its function. Why is it necessary to have a virtual ground as opposed to GND?

For example, in the thread Opamps for Dummies part 2 and 3, https://forum.pedalpcb.com/threads/opamps-for-dummies-part-2.18899/ , by @Chuck D. Bones , what is Vref in relation to the TL072 in the circuit and where is it coming from? is it providing 4.5v to the opamp or is it another ground?

I hope this question makes sense, not sure it does myself haha.

 

[jesuscrisp]

Vref provides basing to half the supply voltage. It's needed because most op amps are basically built for bipolar power, but 9V batteries and standard power supplies only give single supply. Therefore you create Vref and bias the amp in-between 9V and 0V (ground) using a voltage divider.