OT: various electronics questions by "newone"

electronics_field · Post by **electronics_field** » Fri Oct 06, 2006 9:36 pm

cnr 10d471k VARISTOR how to know is short or not by

analog meter

underquark · Post by **underquark** » Sun Oct 08, 2006 3:02 am

Welcome back "newone"?

zaphod7501 · Post by **zaphod7501** » Sun Oct 08, 2006 8:54 am

The Ohmmeter section of an analog meter will tell you the value of a resistor which you then compare with it's markings or the schematic. You usually have to remove it from the circuit first.

You can't check a varistor until you know if it is PTC or NTC. You need to look up it's markings and find out what it is. One type will read "low" and one will read "high". No exact measurement is possible because it varies with voltage and/or current. (and they almost never fail unless they literally burn up).

electronics_field · Post by **electronics_field** » Tue Oct 10, 2006 2:17 pm

how to know IR LED of remote is damage

i have remote i want to check ir led by om meter analog

please reply

Mark Pierson · Post by **Mark Pierson** » Tue Oct 10, 2006 2:52 pm

If you have a digital camera or camcorder with an LCD viewfinder you can use that to see if the IR led works. It will show bright white in the viewfinder.

Post by **The Robman** » Tue Oct 10, 2006 3:29 pm

I wouldn't bother answering any of this guys questions until he shows some evidence that he's actually reading the replies, which he hasn't done yet.

electronics_field · Post by **electronics_field** » Tue Oct 10, 2006 7:36 pm

how to know IR LED of remote is damage

i have remote i want to check ir led by om meter analog

please reply

electronics_field · Post by **electronics_field** » Wed Oct 11, 2006 10:05 am

any help

Post by **The Robman** » Wed Oct 11, 2006 1:28 pm

electronics_field wrote:any help

You've been given lots of help before when you used the "newone" user id, but never one did you post any follow up.

electronics_field · Post by **electronics_field** » Thu Oct 19, 2006 9:54 pm

IS THERE WAY TO CHECK INFRA RED LED IN REMOTE TV IS GOOD OR BROKEN BY ANALOG METER

AND THE INFRA RED LED TESTED TAKE OF FROM REMOTE OR INSIDE

IS THERE PROCEDURE TO CHECK INFRA LED BY ANALOG METER NOT WHOLE REMOTE

johnsfine · Post by **johnsfine** » Fri Oct 20, 2006 5:42 am

The electronic viewfinder of most digital cameras and camcoders will show IR light as white.

That's how most of us test whether an IR LED is working (in an otherwise working remote).

If someone here knew how to check it with a meter they probably would have said so already. I don't think there is a practical way.

I also can't tell whether you mean testing an LED that has been completely disconnected from the remote or while it is still connected.

For completely disconnected, you should look at the spec sheet for a typical IR LED. They all have similar electrical characteristics. You should be able to think of some tests to see if your disconnected LED is close to the correct electrical characteristics. If it is seriously off (such as open circuit) you could conclude it is broken. But I don't know how much it might take to conclude it isn't broken (by that method which is so much harder than using a viewfinder).