1 Ohm Resistor 6

[aware]

Hi all,

I have some RF receivers that accidentally I broke one of the resistors they contain (see photo).
This seems to be 1 ohm 20% resistor (3 band - Brown Black Gold) and I tried to replace it with 1.2 ohms 5% (although the multimeter shows 2 Ohm...) with no luck.

May I please ask:
1) Is it so critical that it must be exactly 1 ohm AND 20%?
2) Shall I assume that maybe after I broke them, I affected them in a non-reversible way?
3) Any other suggestions?

Regards,
Alexis Yannopoulos
Mech. Engineer NTUA, MSc

 

[OperaHouse]

You can have her. I don't want her. Shes too fat for me.

That looks like an inductor, nor a resistor. Seems too short and fat for a resistor.

 

[ScottyUK]

Agree, looks like an inductor. Probably 100[μ]H. Three colour bands aren't standard, so not 100% sure on value: might be 10[μ]H.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[itsmoked]

Measure the broken one with an ohmmeter. Confirm it's an inductor.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[aware]

Thanks for all input.

This green 3-band thing is an inductor?
How do I specify how many henry is? My multimeter doesn't have any scale for H...

 

[itsmoked]

Just measure it in ohms. If it's an inductor you should see almost zero ohms. At very low resistances make sure you take into account the contact resistance.

Measure the ohms by touch both the test leads to different parts of the SAME component lead. Note the reading. Then move one of the test leads to the other side. Note this new reading. Subtract the single lead reading to get the actual resistance.

If it's an inductor as apposed to a resister I would expect something like 0.1 ohms. Again this is measuring the "broken part".

Once confirmed you can then consider the value to possibly be 0.1uH of inductance. Brown,Black,Gold.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[etarhan]

It certainly is an inductor. Unfortunately, color band coding for inductors is not very straightforward, so you will have some trouble to determine its value. However it would be safe to say that it is 0.1 or 1 uH. you can try with both values. If you have a second device, you could use an inductancemeter to measure the value (don't you have a friend in a nearby university, laboratory or college?).

Good luck,
Engin

 

[aware]

Again thanks for all kind help.

So I need to buy some of those in different values.
1) Is it difficult to find them? I searched on the web and found no similiar enclosure for inductors
2) If I test with different Henries, is it possible that I may "burn" it?

Regards,
Alexis Yannopoulos
Mech. Engineer NTUA, MSc

 

[etarhan]

1) They are available dirt cheap in most every electronic component store such as Jameco or your local TV repair shop.
2) No chance of burning anything at all
3) That inductor can not be *that* important. You can even try several wire wound resistors with values between 0.1 to ~2.5 ohms, which is generally available in the junk box of every electronics enthusiast.
4) You can get help from a radio amateur (your local ARRL clubhouse?) nearby. Inductors and transmitters are their specialty, and they are (were) usually helpful guys.

Good luck,
Engin

 

[aware]

Thanks for the advise. I will go tomorrow to buy some (Why the heck they don't simply write the measurement on in Henries?) and test.

Also many thanks for the tip about measuring resistors

Rgds

 

[itsmoked]

They don't write the number because then you can't read the value from all sides.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[aware]

No luck...
Went to a electronics shop - they couldn't find how many Henries my inductor was so they were looking for some with the same color bands. No luck so they gave me some other 4-band inductors that I connected on the PCB with no results.

What shall I do next?

Regards,
Alexis Yannopoulos
Mech. Engineer NTUA, MSc

 

[BobM3]

Maybe the inductor is part of a tuned circuit. A nominal inductor is used and then the connecting capacitors and resistors are choosen to give a certain Q. If so, it would be hard to replace the component and know where you are without a scope and knowledge about how the circuit needs to work.

 

[aware]

Thanks for the reply - may I please ask where (web since I am based in Greece) may I find a collection of such inductors. All inductors I see online are of a different shape and technology. I search and search and search with no matching photos. If I could find some sources, I would send them the photo and ask them to send me some pieces.

Any recommendations and/or suggestions?

Rgds

 

[BobM3]

Epcos makes them:

http://www.epcos.com/inf/30/db/ind_2008/b78108_148t.pdf

 

[itsmoked]

You say the unit doesn't work. How doesn't it work? I'm wondering if something else is busted. As 0.1uH is almost trivially little. And trying others in that ball-park and still having no success - could it be some other failed part?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[aware]

Good question! Well I removed from these RF receivers the buzzer. I removed buzzers from 60 RF receivers and only those that I broke the inductor stopped working i.e. stopped communicating with the transmitter.

I am clueless - what do you make?

Regards,
Alexis Yannopoulos
Mech. Engineer NTUA, MSc

 

[itsmoked]

Have you actually tried a 0.1uH inductor in there yet?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[aware]

I haven't and the reason is that I can't remove one from a working RF receiver since one of the two terminals is "deeply" soldered on the PCB (please see photo attached with my initial message). I wonder, though, if it makes sense to connect in parallel with the terminals of the broken one but then it will actually be two circuits somewhat interleaving each other....

I am afraid it will be rather risky. What do you reckon?

Regards,
Alexis Yannopoulos
Mech. Engineer NTUA, MSc

 

[BobM3]

Do you have the brand name or model? A schematic? Can you tell if the inductor is in the circuit before or after the decoder? In the antenna circuit?