1. We will be in Read Only mode (no new threads, replies, registration) for several hours as we migrate the forums to upgraded software.

convert dc meter to measure ac

Discussion in 'General Electronics Chat' started by lokeycmos, Jan 29, 2010.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    431
    7
    i have an analog dc amp meter that i want to use to measure ac current. im at a loss of ideas. can anyone give me some advice as how to go about this? i figured i could use diodes, but that would rectify the rest of the circuit as well. TY :)
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,444
    1,075
    Convert AC to DC: Opamp+diode+resistors. google "precision rectifier".

    Sense current flowing in conductor: google "Current Transformer"
     
  3. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    431
    7
    sounds like to much work than its worth for my project. i was hoping something much simpler. Ty for your reply. ;)
     
  4. flat5

    Active Member

    Nov 13, 2008
    403
    18
    How sensitive is your meter?
    What is the expected current range?
    What accuracy do you need?
    I'm thinking put a very low value resistor in series and measure the voltage drop across it with a diode in series with one of the meter leads.
     
  5. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    431
    7
    accuracy isnt a big issue. it is a 50mA movement in 5 mA increments. i made a shunt to make it 1 -10amps in 1 amp increments. the reason i want to do this is to measure the current output on my 7 amp variac. that way i will know when it is close to its limit.
     
  6. BillB3857

    AAC Fanatic!

    Feb 28, 2009
    2,493
    389
    Put a bridge rectifier in the circuit. AC lines of go in series with load, + and - leads of bridge to shunt., meter across shunt. It is that easy.
     
Loading...