Understanding Iq

[william2001]

quiescent current, post #3

 

[poseidonsvoice]

”I“ represents current. “q” represents quiescent or steady state.

Best,
Anand.

 

[Toys4Boys]

Big D'uh, I'm typing I and thinking L, only on my second latte

 

[flocchini]

Always enjoyed this explanation that Nelson presented
https://www.passlabs.com/technical_article/power-supplies-commentary-for-consumers/

 

[Toys4Boys]

@flocchini thanks for that link, looks outstanding!

 

[Zen Mod]

Is lq short for something?

depends

problems are complex when there is lacking of


my life became much simpler when I started compensating lack of Iq with increased Iq amps

 

[TungstenAudio]

That’s another excellent article by Pa. Succinct and informative.

 

[Toys4Boys]

From Papa's article, "Typically, a Class AB stereo amplifier rated at 200 watts per channel continuously should be capable of delivering 700 watts or so, and this means a transformer rating of about 2000 watts. Anything less means non-continuous operation." Is there a mathematical calculation being done in the background?

 

[Toys4Boys]

problems are complex when there is lacking of

Not certain, but if you want to disparage me it would help if I understood

 

[jamesfeline]

So sorry could not resist this one .... (apologies to the female members)
before I get banned ... its a joke honestly

 

[william2001]

As far as transformer sizing goes, and which VA rating to choose.... I would look at the total expected dissipation of the amplifier, and go with one that has a rating at least twice that (2 to 1 margin).

 

[Zen Mod]

there is Papa's article even for that

 

[jamesfeline]

Electronics and making things should be fun ......

 

[Toys4Boys]

Electronics and making things should be fun

The older that I get the more I follow, if it ain't fun why bother?

 

[Dennis Hui]

A fun little book is Mims' "Getting Started In Electronics". I remember picking up a copy at a Radio Shack in the 80s.

 

[Toys4Boys]

@Dennis Hui Radio Shack, wow that brings back memories.

 

[Toys4Boys]

OMG! I think that I'm starting to gain a little understanding of amplifier design.

 

[Philbo King]

Reading thru this I again wondered why voltage is represented by E. With a little help from google I ended up on Fluke's Learning page, looks like a nice simple explanation for many electrical terms etc. Seems like a valuable resource for those of us wanting to follow along when the SMart guys on here speak.

Also started listening to the link supplied by @wdecho, but that gonna take some time and serious concentration. Time I seem to have, concentration.....

E stands for electromotive force which is a long way of saying voltage.

 

[wdecho]

Redneck language, E or V is the force that gets the electrons, I or current, moving. You must have an electron flow and V is that force. Everything else in the device, circuit, is, has, R, resistance.

 

[steveu]

You should appreciate that "Iq" is not a common engineering variable and is a somewhat arbitrary variable designator probably referring to the bias current in amplifier output circuits. It means nothing to those outside the amplifier design community and may just as well be called something else like "idle current" or "cross-over bias". For class-A amplifiers, "Iq" will be the peak output current. For class-AB, "Iq" will be about 1% of the peak output current. For class-B "Iq" will be a tiny current near zero. For class-C, Iq=0. If you Google "bias current", you will find lots of articles because that is a more common description.