Is your unoptainium power switch worth $5 and an hour or so of your time?

Discussion in 'Solid State' started by K7sparky, Feb 26, 2013.

  1. K7sparky

    K7sparky AK Subscriber Subscriber

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    A quick look at the Littlefuse and ST data sheets show both have a linear temperature dissipation of about 1 watt per 1 A continuous RMS current within the amp rating of the device.

    If your amp gobbles up 3 amps, then the TRIAC has to dissipate 3 watts and is independent of the current rating of the TRIAC.
     
    Last edited: Jan 7, 2017
  2. c.coyle

    c.coyle Fighting the Dunning-Kruger Effect Subscriber

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    Do you feel comfortable getting them off Ebay?
     
  3. K7sparky

    K7sparky AK Subscriber Subscriber

    Messages:
    234
    Location:
    Great State of West TN
    So far have had no problems with new parts. Then again 20A 600V is so overkill what could go wrong - go wrong - go wrong - go wrong

    Got a few transistors listed on the bay as NOS and am guessing were rejects that didn't work in the switching PS from a Motorola service monitor. One of the fussiest applications I have done battle with.

    Luckily a friend mentioned the identical with higher voltage I had overlooked - again on eBay that were new run direct from BOCA Semi out of Florida which worked fine. Before BOCA they had been obsolete for years.

    I have a pile of both regular and Darlington some with Ft well into the mHz for switcher application that wouldn't work in the 20 kHz switcher that I had thought any old audio transistor would work in.

    If parts come from the other side of a pond patience is a necessary virtue.

    In general I get most parts from Mouser or DigiKey as I don't want to wait and only need a few of this and that.

    I use enough TRIACs it was worth the wait to get 50 to try and still have some of the Littlefuse ones on hand. Always feel better with more than one source.

    A few things like coated fiber glass tubing of sizes I don't have rolls of come from China / HK. Thinner than the stuff I have rolls of but fine for low voltage.

    BTW love Alfred E Newman with a soldering gun
     

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