Voltage across an open switch

Discussion in 'Homework Help' started by fahadali, Jun 8, 2009.

  1. fahadali

    Thread Starter New Member

    Jun 8, 2009
    Hello I was wondering if we had a circuit with an open switch, what would the voltage be across the (SWITCH).

    thank you
  2. vvkannan

    Active Member

    Aug 9, 2008
    hi fahadali,

    I think it would depend on the circuit.If its a simple series circuit with a resistor connected across a voltage source then the supple voltage is the voltage across the open circuit.You can consider the open switch as infinte resistance and by apply voltage division rule almost all the source drops across the open switch.In the case of complex circuits i think you can find the thevenin's equivalent voltage which would be the voltage across the switch.
  3. gryskop


    Mar 1, 2008
    The voltage across an open switch will be the same as the circuit Vcc.

    The voltage across a closed switch will be zero volt (or close to zero) depending on the internal resistance of the switch contact. A closed switch can be seen as a simple piece of wire, with basically no volt drop across the terminals.
  4. fahadali

    Thread Starter New Member

    Jun 8, 2009
    it is a series circuit with two lamps connected in series, i guess it should be the supply voltage