How exactly do voltage regulators work?

Discussion in 'General Electronics Chat' started by XOIIO, May 26, 2013.

  1. XOIIO

    Thread Starter Member

    Mar 1, 2013
    So I was wondering, just how to voltage regulators (like the 7805) work? The most in depth answer I got was that they compare the output to the source and use the difference to keep it stable but how exactly do they regulate voltage?
  2. MrChips


    Oct 2, 2009
    A linear voltage regulator is a feedback control system using an op amp.

    The output voltage of an opamp is given as

    Vout = A(V2 - V1)


    A = voltage gain
    V2 and V1 are the non-inverting and inverting inputs.

    If you pick off the output voltage of the regulator and feed it back into the V1 input of the opamp (negative feedback) you can make the opamp regulate its output.
    screen1988 likes this.
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    If look at the datasheet on page 2, you will see there is a precision zener diode inside one.

    How it works.
    Last edited: May 27, 2013