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Hi!
Audio Transformer means A Tranformer which covers the audio freq range from 50Hz to about 10kHz as compared to Power Transformers which generally operate at either 50 or 50 Hz only.
Audio transformer is generally used for galvanic isolation.
Having designed some audio transformers over the years, I can say this: If it should support full audio bandwith, it must have double or threefold winding count compared to a 50 Hz transformer, which also implies increased size. And it must have interlaced windings to reduce stray inductance. This applies to signal transformers as well as to power transformers.
Joe1986,
In addition to FvM's comments, audio transformers are designed to have low distortion. This means that the flux density is kept lower than what would be used in a power transformer for a given core material. This reduces distortion due to non-linearity in the B-H characteristic of the core material. In general, this means that for a given voltage range, the core material must be physically larger than for a power transformer using the same core material. Core materials that are used for audio transformers are designed to have high initial permeability, which allows the use of fewer turns for a given primary inductance.
Regards,
Kral
audio transformer are used for impedance matching between the output of ampilifier and the load(which is speaker with low impedance) in order to apply the max power to the load or speaker.
if you are interested i can send the formula and prove for this case.
ya sure please go ahead and send the formula........i thank all the above users for coming forward and sharing their quality knowledge
Added after 2 minutes:
what i also wanted to know is that when 230v ac mains is given at the primary winding of a transformer.............what is obtained at the secondary winding???
Depends on the load and the ratio between primary and secondary number of turns. You can get a very wide range of possible outputs depending on the transformer...
ya sure please go ahead and send the formula........i thank all the above users for coming forward and sharing their quality knowledge
Added after 2 minutes:
what i also wanted to know is that when 230v ac mains is given at the primary winding of a transformer.............what is obtained at the secondary winding???
It hasn't become clear yet for which purpos you want to use a transformer with speakers? The only common used I application I know is "100 volts" technique for longer distance speaker cabling, sometimes used e. g. at public areas or large buildings. It utilizes up transformer at the amplifier and down transformer at each speaker. Sometimes, it may desirable to have a transformer for exact speaker to amplifier matching to maximize power output, but a larger amplifier could be cheaper than an additional transformer.
Most general purpose speakers are 4 or 8 ohms, rarely 16 ohms. This is nominal impedance, exact value can be somewhat different. With most standard (voicecoil driver) speakers, DC resistance is 5 to 20 % below nominal impedance.
joe1986,
An Ohmmeter will give you the DC resistance of the speaker voice coil. The impedance varies with frequency. It is a function of the electrical parameters (resistance and inductance), the suspension system, and other parameters (even the position of the speaker in the measurement room). One way to measure it is to apply a voltage to the speaker, and measure the magnitude and phase of the current. The impedance is equal to V/I, taking into acount the phase. It is a complex number that varies with frequency. "Testing Loudspeakers" by Joseph D'Appolito has a very good section on speaker impedance measurement.
Regards,
Kral
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