Questions on Voltage measurement

Discussion in 'Homework Help' started by Viann, Jul 9, 2009.

  1. Viann

    Thread Starter New Member

    Jun 16, 2009

    Well.. alright, say I want to measure Voltage used by an appliance from the mains of 240V/50Hz.

    Various methods where one of them include stepping down the voltage to about 5V and using the PIC to perform calculation and then display it using an external device.

    My question is, if the mains offer 240V, won't the reading always be 240V, due to the fact the stepping down is done internally by the appliance (i.e. step down -> convert ACV to DCV)?
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
    Please be very careful if you are dealing with 240 volt mains.

    It can easily kill at worst or destroy equipment at least.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    This is a confusing statement -
    First, you know that the appliance is fed by 240VAC, so measuring only confirms what you know. If the unknown appliance is something like a stove, it may only use 240 VAC. If it has internal circuitry, then there will be a stepdown transformer and rectifier to supply DC power to the circuitry.

    But back to the thing to be measured - could you mean measuring current used by the appliance rather than the voltage?