voltage regulator overheating

[dazed & confused]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:


Thanks,
Bruce in Fresno (designing how power motor speed controller.)

 

[neon]

BOTH are the same without current out lame guy.

 

[TTman]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:

Suck it and see.... LITERALLY

 

[Rene Tschaggelar]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:

The dissipated power is the voltage difference over the regulator times
the current.

 

[Jasen Betts]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:

the one with the undersized heatsink.

 

[JW]

The 15 volt one.

My answer? Do your own damn homework. You aren't doing yourself
any favors by trying to cheat. Even if someone does give you the
answers, you will be unprepared to pass your finals and unprepared
to get a job.

Me? I'm trying to cut down on the competition.

 

[Martin Brown]

the one with the undersized heatsink.

I once had one overheat because it was clamped onto shiny bright
aluminium box.
The ones on black anodised aluminium of the same size were fine. A
coat of paint cured it.

Regards,
Martin Brown

 

[[email protected]]

I once had one overheat because it was clamped onto shiny bright
aluminium box.
The ones on black anodised aluminium of the same size were fine. A
coat of paint cured it.

Regards,
Martin Brown

Just do not use it in the sun.

 

[Eeyore]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:

Depends on the load on each of course !

Exam question was it ?

Graham

 

[Eeyore]

the one with the undersized heatsink.

Oh so true !

Graham

 

[Eeyore]

Just do not use it in the sun.

Ah yes ! Many decades ago I modified some photographic timers to operate
from a 12V battery using a 78Lxx regulator. The load was quite light and
they operated fine.

Or at least they were fine until one job involved filming for weeks in
an impromptu greehouse on top of their premises' roof !

About a week or so in, the system stopped filming. Examination of the
timer showed 3 bare leads where the regulator had once been and some
black plastic debris. A TO-220 version fixed it.

Graham

 

[Ross Herbert]

On Sun, 7 Dec 2008 20:27:31 -0800 (PST), "dazed & confused"

:MY QUESTION: Suppose you have two voltage regulators that both are
:configured to output 12 volts. If the first one has a voltage input
f 25 volts and the second one has a voltage input of 15 volts, which
ne gets hotter?
:YOUR ANSWER:
:
:
:Thanks,
:Bruce in Fresno (designing how power motor speed controller.)


You didn't specify the load for each case. If you have no load on either one
then they will both be the same temperature - cool.

 

[JosephKK]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:


Thanks,
Bruce in Fresno (designing how power motor speed controller.)

First, answer two more questions: Each at what current? Each what
circuit type / topology? I do not care to guess in the dark.

 

[Ecnerwal]

MY QUESTION: Suppose you have two voltage regulators that both are
configured to output 12 volts. If the first one has a voltage input
of 25 volts and the second one has a voltage input of 15 volts, which
one gets hotter?
YOUR ANSWER:

The one putting out 100 Amps, rather than 100 milliAmps.

The one that isn't a switcher.

The one not in a bath of liquid nitrogen.

++++++++++++

As in, not nearly enough is specified in this question (or is it a
homework problem you were supposed to pick holes in yourself?)