need some help with unknow component.

[shlomi93]

hey guys.
so im trying to fix a monitor and i have on the board TO92 component
the component is A1 AS431A CO828
now the pins on the board is R A C
REF
ANODE
CATHODE
but i dont know what component have R C A pin out.
im a beginner.
please help me to identify this component becuse i really donst get it.
and if i cannot fine the same component what can i solder instead?

datasheet Attached.

thanks in advance.

[stj]

Re: need some help with unknow component.

431 voltage reference.
very common - the letters change but the part does not.
TL431 is the most common.

[shlomi93]

Re: need some help with unknow component.

431 voltage reference.
very common - the letters change but the part does not.
TL431 is the most common.

what?
so R C A = C B E ?
and how do i test this component with DMM ? i already desolded it from the board..

[mariushm]

Re: need some help with unknow component.

It's not a transistor, so there's no collector, base and emitter. It's sort of a diode.

See http://www.homemade-circuits.com/201...regulator.html

Try to use Google from time to time, it's often faster than waiting for answers on a forum.

[SteveNielsen]

Re: need some help with unknow component.

No, it is a voltage regulator IC. Think of it like a variable zener diode.

[rievax_60]

Re: need some help with unknow component.

That link has useful information.
I have never tested a TL431 with a meter. Red to A and Black to C on diode test should read open. Connecting R to A should cause a 2.5v reading or slightly less.
Never run a power supply with the TL431 removed. It is an important part of the voltage regulation loop.