Testing Frequency

Discussion in 'General Electronics Chat' started by ShockBoy, Aug 12, 2010.

  1. ShockBoy

    Thread Starter Senior Member

    Oct 27, 2009
    I was wondering if there is a way, other than an oscilloscope, for testing frequency? Like would a standard incandescent light bulb/fixture flicker at 50 hertz? Something like that. Thanks.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. bradstormer


    Aug 6, 2010
    some multi-meters come with built in frequency counters. just pop the probes in and wham.. you get your frequency..
  4. ShockBoy

    Thread Starter Senior Member

    Oct 27, 2009
    Gonzo is right, wow.

    I've got the Cen-Tech digital multimeter(red elcheapo), but am not sure what to look for on it.
  5. Norfindel

    AAC Fanatic!

    Mar 6, 2008
  6. Jaguarjoe

    Active Member

    Apr 7, 2010
    Be careful- As long as you know you have have nice waveforms or nice pulses, a frequency counter is great. If you're looking at garbage like auto ignitions, a scope might be better.
    The best of both worlds is a scope with a built in frequency counter.
  7. someonesdad

    Senior Member

    Jul 7, 2009
    An old method (from the early 1900's) was to put a strong magnet next to the filament of an incandescent lamp. If the hot wire got kind of "fuzzy", you'd know it was being driven by an AC voltage rather than a DC voltage. It obviously won't measure the frequency without some help though.

    There were also frequency meters that had tuned thingies that vibrated near the line frequency. There would be a row of them that would e.g. let you monitor frequencies near the line frequency. I've got one somewhere out in the shop, but I'm too lazy to go get it and write down the model/name...

    True frequency counters are the best for careful measurement, but are usually beyond the needs of the average hobbyist. Modern DMMs often have a frequency measurement (even my 20 year old Fluke 83 does). Modern digital scopes are pretty good too, as they can be set to both show the waveform and measure its frequency.