In article ,
says...
FWIW In the power amp I was referring to, I've used one for 20+ years, and
a second for about 10 years, with no fuse failures.


I was always taught that a transistor was an expensive device designed
to protect a fuse..

T.
--
Do Binary Tripods have 11 legs ?

Tony Gartshore wrote:
In article ,
says...
FWIW In the power amp I was referring to, I've used one for 20+ years, and
a second for about 10 years, with no fuse failures.


I was always taught that a transistor was an expensive device designed
to protect a fuse..

T.

My first proper transistor amplifier (I don't count the Sinclair
Z-12)was a 30 watt design published in (I think) Practical Electronics
which had a stabilised power supply in which the series regulator
transistor would blow to protect the fuse.

S.



--
http://audiopages.googlepages.com

In article , Tony Gartshore
wrote:
In article ,
says...
FWIW In the power amp I was referring to, I've used one for 20+ years,
and a second for about 10 years, with no fuse failures.


I was always taught that a transistor was an expensive device designed
to protect a fuse..

That can very easily be the case. :-)

The trick is to understand the way fuses behave and the details of the
current waveforms.

This often means that the fuse value you choose is well below the peak
current levels you are concerned about. Thus in the example I was
describing, the fuses were a 5A nominally 'fast' type. Yet the amplifier
would cheerfully give peak currents well above 30A on both sinewave tests
and music without the fuses blowing. Yet the fuses protected the
transistors from a short. I suspect that 2A fuses would actually have been
fine for almost all normal use, but 5A ones did the job OK.

However, simply choosing 30A fuses would have been a recipy for disaster!
;-

Slainte,

Jim

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