Switching on and off a relay using the TL431

Discussion in 'General Electronics Chat' started by RodneyB, Mar 12, 2015.

  1. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    I have been working on a low voltage cut out switch and have had extensive help here on this forum. With the guidelines I think I have made progress.

    I am wanting to switch off a relay through a BC547 when the voltage drops to a Preset level.

    On the circuit I have been using the voltage between the cathode and ground stays at 2.7 Volts as I reduce the voltage it suddenly switches to 1o.6 Volts This is when the load must be switched out.

    I was using a IRF9540 but it never switches off and I have no idea why. Thus wanting to try another circuit.

    The circuit I was given is on a post of mine titled low voltage cut out
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    post your circuit... Ideally your going to need a comparator to set the switch off voltage.
    RodneyB likes this.