I would like to build a test circuit to check if the TL431 in my circuit is faulty or not. I found this circuit when doing an internet search, however there was no description as to how it works.

Is this circuit suitable and how does it work?

Thanks

 

the voltage is set by the formula.

10K/2.4K + 1 x 2.5v = set voltage

with the values shown thats 12.9V

 

the voltage is set by the formula.

10K/2.4K x 2.5V = + 1 = set voltage

with the values shown thats 11.4V

Thank you.

Does this mean the LED will only come on at 11.4 Volts?

 

no,
12.9v

 

no,
12.9v

Thank you I don't know where I got the 11.4 Volts from.

 

I would like to build a test circuit to check if the TL431 in my circuit is faulty or not. I found this circuit when doing an internet search, however there was no description as to how it works.

Is this circuit suitable and how does it work?

Thanks

The simplest test is just connect Vin to cathode and it should behave like a 2.5V zener.

It needs at least 1mA and the maximum current is 100mA - as long as you make sure it doesn't exceed the dissipation limit.

Its actually a comparator with a built in 2.5V reference.