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transformer id

Discussion in 'Electronic Basics' started by Shane Kirkman, Sep 24, 2003.

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  1. Being a dumbo can someone tell me what a 1200 to 8ohm audio power
    transformer is in DickSmith catalog language, or close to it.
    --



    Eat-Drink-Smoke and be Happy.
    Shane.
     
  2. Baphomet

    Baphomet Guest

    1200 ohms and 8 ohms represent what's called impedance, or resistance to the
    flow of A.C. current. For maximum power transfer (that's what you're looking
    for in an output stage), 8 ohms is the secondary and should match the
    impedance of
    your speaker. 1200 ohms is the primary impedance through which the collector
    of the output transistor or plate of the output tube would receive its
    supply voltage. The primary impedance (1200 ohms) is the load across which
    the output stage develops its voltage to be fed to the speaker vis a vis the
    x-fmr. In this
    particular case, the turns ratio of the x-fmr is about 12:1 which means that
    the output voltage to the speaker will be about 1/12 th. that of the primary
    voltage. Working backward from the load (speaker), knowing how much power
    you need to drive your speaker will determine how much voltage you will need
    to develop across the primary x-fmr. winding (within the power handling
    capacity of the x-fmr., speaker, and output stage...of course :)

    If you haven't fallen sound asleep by this time, assume that you want to
    drive your speaker with one watt of rms power (2.8 vrms). In a perfect
    world,
    you would need to develop about 34 vrms. across the primary winding of this
    x-fmr...zzzzzzz

    P.S - Smoke what?
     
  3. Fred Abse

    Fred Abse Guest

    No you're not, you're looking to present the load to the output device
    which will operate it at a specified output power and distortion.

    "Image" power matching is seldom if ever the same thing. The *optimum*
    load for a device is almost never its "looking backwards" output
    impedance.
     
  4. It's not for a speaker. It's for a personal protection device for my wife.
    P.S - Smoke what? Not cigarettes there bad for your health. ;)
     
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