how hot can a transistor get

[j van c]

I changed a transistor on a print with another recommanded transistor.
He's getting quite hot. I can't hold my finger on it.
Is this normal?

 

[colin]

"j van c" <jvancxyz@pandora.be> wrote in message
news:AQP4d.299$XT2.55304208@hestia.telenet-ops.be...

I changed a transistor on a print with another recommanded transistor.
He's getting quite hot. I can't hold my finger on it.
Is this normal?

in my experience transistors can work quite hapily but be to hot to touch
for any lenght of time,
however i seem to have more sensitive fingers than most people,
also if it leaves a mark on your finger or even takes skin off then i would
say its too hot, especialy if it has any heatsink.
this ocurs much above 60'c i think wich means the silicon is probably a lot
more,
but typicaly silicon devices are speced up to over 100'c, but reliability
goes down with increasing temp.

Colin =^.^=

 

[Wayne]

It is not uncommon for say automotive spec devices to operate between -40 to
125degC (- 105 + 20degC Delta for board temp) and junction temperatures of
upto 150degC. Check the datasheet for that device, it should have the
operating temperature range. If the pervoius device did not get hot then
the char. of that transistor must differer to the original and how much more
"heat" it can withstand will again be in the datasheet.

Wayne

"colin" <no.spam.for.me@ntlworld.com> wrote in message
news:a_P4d.32$Ej.19@newsfe2-gui.ntli.net...

"j van c" <jvancxyz@pandora.be> wrote in message
news:AQP4d.299$XT2.55304208@hestia.telenet-ops.be...
I changed a transistor on a print with another recommanded transistor.
He's getting quite hot. I can't hold my finger on it.
Is this normal?



in my experience transistors can work quite hapily but be to hot to touch
for any lenght of time,
however i seem to have more sensitive fingers than most people,
also if it leaves a mark on your finger or even takes skin off then i
would
say its too hot, especialy if it has any heatsink.
this ocurs much above 60'c i think wich means the silicon is probably a
lot
more,
but typicaly silicon devices are speced up to over 100'c, but reliability
goes down with increasing temp.

Colin =^.^=

 

[Jamie]

no
put a heat shink on it.
it depends also on how fast it gets
...


j van c wrote:

I changed a transistor on a print with another recommanded transistor.
He's getting quite hot. I can't hold my finger on it.
Is this normal?