Ideal Biasing Current

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Howdy...

Quick question.....

What should be the ideal biasing current for a 2n3055 transistor. I live in a part of the world where temp goes up to 45 degree Celsius during summers. So for me power dissipation is a big concern....

In want the transistors to perform optimally yet not overheat.

Any suggestions?
 
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There is no quick answer because it doesn't quite work like that.

The ideal bias point for a given amplifier depends on the circuit configuration and the component values used.

A CFP type output stage would have the lowest ideal bias point, somewhere around 10 milliamps or less.

You may well find that for most amplifiers you will not notice any deterioration in audible sound quality even if you turn the bias down considerably.
 
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That is a quasi complementary output stage.

21 mv across 0.6 ohm is giving around 35 milliamps which sounds quite high actually. Something nearer 8 milliamps would be nearer the mark I would have thought.

The real problem in setting it low is to ensure the bias generator can maintain that set current through all ambient temperature ranges.
 
"Ideal Biasing Current................What should be the ideal biasing current for a 2n3055 transistor...............
this is wrong. It is not current that you need to set.

..............Right now I have bias set close to 21mv
This is more correct. But that 21mV is the value usually adopted for an EF output stage.
The CFP is roughly a bit less than half the voltage normally.

D.Self gave some numbers for the bias voltage for EF (2.86 to 2.93Vbias) and CFP (1.297 to 1.298Vbias) output stages. For a quasi complementary output stage which is half EF and half CFP, it turns out that a Vbias similar to a CFP gives lowest crossover distortion. On that basis I would look at using 1.297Vbias, until I could measure for lowest crossover distortion (this corresponds to the 8 to 10mVre that Mooly talks about).
Most of this information is posted on the web where D.Self's articles from WW were copied.
D.Self's Vbias is across the Vbe multiplier, after the Radjust resistor. You need to read his articles/book.
 
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