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Working of Pulse Input Speed Indicator

  1. Feb 12, 2012 #1

    Can anyone please tell me how a pulse input speed indicator works and how one can be calibrated? :smile:

    Thanx a lot!
  2. jcsd
  3. Feb 13, 2012 #2


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    Science Advisor

    These can be analog or digital.

    You need to know how many pulses are being received each second because this is related to the speed you need to know.

    So, if these pulses are a constant width, then the average voltage because of them will depend on how many of them are received each second. So, you can just filter them to get a steady voltage and then apply the output to a meter.
    The reading will depend on the number of pulses being received each second.
    This is the analog method.

    Digital is even easier. You just count the pulses for one second and the reading is the number of pulses per second. In this case, 1 second is called the "gating time".

    Calibration depends on the actual application. If it was speed of a car, you could use a GPS as a reference speed and compare it with the actual reading being obtained.
    You could then adjust the pulse width in the analog system or the gating time for the digital system until the readin was correct.
  4. Feb 13, 2012 #3
    Hey! Thanx a lot! Explained it nice and short - just what I was searching for. :smile:
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