optoisolator testing question

1

1-3-2-4

Member

• May 26, 2013

• #1

It's been awhile since I had to mess with one but on the collector & emitter side should it be showing open? I have a strong feeling it should not..

 

K

kubeek

Well-Known Member

Most Helpful Member

• May 26, 2013

• #2

Hm, hope you mean when the diode is off - what do you measure on a normal transistor between E and C? If it did not show open it would not be a very good transistor..

 

K

kubeek

Well-Known Member

Most Helpful Member

• May 26, 2013

• #3

double post

 

1

1-3-2-4

Member

• May 26, 2013

• #4

It shows open

 

1

1-3-2-4

Member

• May 26, 2013

• #5

I was looking at this here and mine does not match up which was why I was asking

**broken link removed**

Never mind they are fine

 

Last edited: May 26, 2013

dr pepper

Well-Known Member

Most Helpful Member

• May 28, 2013

• #6

If you have 2 meters, connect one as a diode test accros the led side, you should get around 2v, with the diode test still in place measure the reistance of the tranny side, with the black probe to the emitter, should be a few ohms which will turn to infinity when you remove the diode test from the led side.
I use this test on dead smpsu's.