Positive potential measured

Discussion in 'General Electronics Chat' started by Webby, Jul 22, 2014.

  1. Webby

    Thread Starter Active Member

    Jun 15, 2008
    Im trying to understand the meaning of positive potential in a 12v circuit, i.e if the connection to earth on a switch is interuppted would a positive potential be measured on the switches earth when the switch is closed?

    I can only presume no as the circuit is incomplete and no curret flow?
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    if there is a positive voltage on the ground side of a switch when the switch is closed, there is a bad ground. current flow causes a voltage drop.
    I have a 40 year old car, and thats how you check things. from the ground terminal of the lights to the negatie terminal of the battery, if theres voltage when the lights are turned on, theres a bad ground (corrosion)