Is there a DC clamp on Amp Meter?

Discussion in 'General Electronics Chat' started by foolios, Aug 9, 2014.

  1. foolios

    Thread Starter Active Member

    Feb 4, 2009
    I was just looking at the clamp meters at the store to purchase something to measure amps coming out of my battery. Then realized they aren't for DC.
    So then I also realized these things work via magnetic field which is prolly why I don't see any for DC.

    Is there a way to use a clamp on device then? Or must the amp meter be tied in series with the circuit? Never did this with DC before and am still trying to get my head around the differences that I am running into from AC to DC.

    Thanks in advance for any provided info.
  2. inwo

    Well-Known Member

    Nov 7, 2013
    Yes there are.
    You may be disappointed though.
    They are subject to more errors than ac meters and don't reset to zero easily.

    Unfortunately, the model I have is no longer made.
    I really like it for ball park high dc amps.
    foolios likes this.
  3. foolios

    Thread Starter Active Member

    Feb 4, 2009
    Thanks for letting me know that they do exist.
    Well, I guess if they aren't very accurate anyways, I'll just wire inline a cheap gizmo from eBay.
  4. MaxHeadRoom


    Jul 18, 2013
    You can also get a AC/DC clamp on attachment for your VO meter. Fluke etc.
  5. wmodavis

    Well-Known Member

    Oct 23, 2010
    I have and regularly use a clamp-on ammeter that works both on AC & DC. Mine is a Klein Tools CL2000 purchased at Home Depot in the US for ~$140. I would not be without it and am highly pleased with it though all meters have down sides. It is a true RMS meter which is the primary reason I got it but also measures capacitance, AC/DC microamps, Hz/DutyCycle & has a HOLD and MIN/MAX function. Here is a link to amazon ad for it.
  6. crutschow


    Mar 14, 2008
    Both AC and DC clamp-on ammeters use the magnetic field surrounding the wire for measurement of the current. The difference is that the AC field is varying so you can use a transformer to measure the current. The wire going through the clamp is the primary and the clamp is a magnetic material wound with wire to be the secondary.

    To measure DC you need a device sensitive to a static magnetic field, so obviously a transformer design won't work. DC units thus use a Hall-effect sensor or other DC magnetic field sensitive device. This generally costs more than a simple transformer, making DC sensitive clamp-on ammeters more expensive and less common.

    You can also buy simple ammeters that are placed on the wire to measure the DC current. They are passive units with the magnetic field directly deflecting the meter (likely a small magnet connected directly to the meter movement) and, for this reason, are quite insensitive, suitable for measuring only large currents such as the starter current draw in a vehicle.
  7. ian field

    Distinguished Member

    Oct 27, 2012
    AFAIK; the hall-effect ones work for DC.

    You can also get hall-effect high-side current sensor chips - they're pretty much a bar of metal through the package with solderable ends and a hall sensor encapsulated with it.
  8. Lestraveled

    Well-Known Member

    May 19, 2014
    I really like my AC/DC clamp on amp meter. It is true RMS reading and has proven itself to be very accurate.

    Note: Hall effect sensors are used for AC and DC current sensing.