Frequency output of simple dimmer circuit

Discussion in 'General Electronics Chat' started by Willen, Oct 27, 2017.

  1. Willen

    Thread Starter Member

    Nov 13, 2015
    265
    27
    I am seeing a way to use these types of diac triac based circuit to control various types of small devices. Some device might critical to supply frequency.

    willen Figure3.png

    I know charging and discharging time determines the gate triggering. According to gate trigger pulses frequency, does the circuit produce different frequency too? Or output frequency will be same as mains frequency?
     
    Last edited by a moderator: Oct 27, 2017
  2. bertus

    Administrator

    Apr 5, 2008
    18,598
    3,605
    Hello,

    The following set of application notes will give you a lot of info on the circuit.
    Your circuit is given in the AN1003 section.
    It is using phase shifting on the mains ferquency.

    Bertus
     
  3. Ramussons

    Well-Known Member

    May 3, 2013
    747
    129
    Even though the RC combination can have a lower time constant for a frequency > 50 / 60 Hz, the capacitor gets charged only once every half cycle. Because, once the Thyristor is triggered, there is no voltage to charge the capacitor again. At the end of the half cycle, the thyristor turns off and then the capacitor starts to charge for the next half cycle. This repeats.
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    8,751
    2,020
    The load sees essentially mains frequency, but harmonics (predominantly odd harmonics) of that will be present.
    Harmonics.PNG
     
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