Home made DCC meter

MK Jan 18, 2020

  1. MK

    MK TrainBoard Member

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    Since my club does a lot of shows, this would answer the question that is asked (usually yelled!) 100x during setup "Is track power turned on or is this module not connected???!!!" [​IMG]

    Home made DCC meter.
     

    Attached Files:

  2. catfan

    catfan TrainBoard Member

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    MK-

    Was this a component build? I'd sure find this handy even on the home layout.

    Thanks
     
  3. MK

    MK TrainBoard Member

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    Mark, yes it was but a simple one. Small project box that is bigger than the DC volt meter. Meter can measure 3-30V DC. It's self powered so no additional voltage regulator needed.

    Glue two short lengths of track to the two sides and bring the wires into the box. Tie them to a bridge rectifier so meter can read the DC output.

    Took my true RMS Fluke meter and measure the DCC voltage. If you don't have a true RMS meter you can measure Rail A and B to Ground and add the two readings.

    The DC meter is adjustable by a small pot. Adjust to match the readout of the Fluke meter. So the DC meter is skewed to "measure" a DCC voltage.

    I got all the components at Allelectronics.

    $13 in parts. :LOL:. (But shipping was $8.)
     
  4. Rich_S

    Rich_S TrainBoard Member

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    I'm curious, what is the difference in the voltage readings when you measure the DCC voltage in true RMS and then in VAC? How much of a difference is there?
     
  5. MK

    MK TrainBoard Member

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    Rich, the difference was negligent for my purpose.

    14.41 VAC in True RMS.
    7.19 VAC in Rail A/B to Ground, so 14.38 VAC total.

    In DC mode coming out of the bridge rectifier i get 13.00 VDC. So I adjusted the meter to give me a false reading of 14.4V. Thus my DCC Measurement Only warning label. :D

    All measurements taken with a Fluke multimeter.

    I know this is not as accurate as the RRampmeter which has special circuitry but close enough for my purpose and the price was right. :)
     
    Carl Sowell, Rich_S and mtntrainman like this.
  6. vasilis

    vasilis TrainBoard Member

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    for 2$ from ebay or aliexpress digital ammeter voltmeter + 1$ bridge etc.
    on the other hand, yours can't be lost:LOL:
     

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