transformer id

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

1. Shane KirkmanGuest

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. BaphometGuest

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 AbseGuest

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. Shane KirkmanGuest

It's not for a speaker. It's for a personal protection device for my wife.