What makes a good pass transistor in a serie regulator

[timgrindell]

ST901T

I have used the darlington ST901T in a cap multiplier circuit; would it be any good as a pass transistor in a series regulator?

ST901T datasheet

tim

 

[bansuri]

1. All published circuits will blow up when shorted.
2. A 1mm copper wire will have 10mOhm with 2x25cm
3. What circuit needs such a low impedance?
4 It requires sense wires to reach that low
5. You can easily implement even a negative output impedance or exactly 0mOhm

.

 

[mchambin]

Join Date: Aug 2008
Location: Dolceacqua
1. All published circuits will blow up when shorted.

Sure they do, so what. These are for people who know what they are doing. It is not for a lab PSU as is. In that case, one would add the adequate protection circuitry, or consider the pass device is a fuse.

3. What circuit needs such a low impedance?

That is a good question.
Are they rational answers ?

 

[mchambin]

I have used the darlington ST901T in a cap multiplier circuit; would it be any good as a pass transistor in a series regulator?

ST901T datasheet

tim

Looks good to me.
I like it's 1.25 ℃/W Thermal resistance Junction to Case.

 

[Mark Johnson]

John Walton's voltage regulator comparison article in Linear Audio, also included human listener preference data. He calculated tables of correlation coefficients, to find out which electrical measurements were best correlated to listener preference. Regulator output impedance was one of the measurements whose correlations were tabulated.

The article is available as an individual download (so you don't pay for all of the other articles in the entire volume) for € 2,99

 

[mchambin]

IMO the subjectivist approach doesn't qualify as rational. It is border line, a clever workaround.

 

[Elvee]

Yes, probably. Allow me some time.

The measurements are here:
Just for fun: a superreg with <12 discretes??! ?! ?

 

[jan.didden]

IMO the subjectivist approach doesn't qualify as rational. It is border line, a clever workaround.

I don't understand what you mean here. Can you explain a bit more what you mean?

Jan

 

[mchambin]

My sarcastic comment was about John Walton's voltage regulator comparison article in Linear Audio.
There are ingredients of scientific methods.
Words like correlation tables coefficients
But who knows about test conditions.
Only double blind test can prove something.
There is a look of rationality, but all we have actually, are opinions.