[SOLVED] How do I determine if a component is a resistor or an inductor?

[lee321987]

I bought some some components labeled as resistors from a surplus store.
I've attached a picture of one of them. It has flat ends (not rounded like most resistors I see). Also, the first band (silver) is much wider than all the other bands.
Is there any way to make sure this is a resistor and NOT an inductor?
The only test devices I have are two multimeters.

Also, am I right that all carbon film resistors have rounded ends, and all carbon composition resistors have flat ends?

 

[Phytech]

It's easy to identify if you have a multimeter. Measure the resistance: if it is a short it's an inductor, if you get a resistor value (which should be close to the value from the color code) it is a resistor.

 

[enjunear]

It looks like an inductor (carbon film resistors are usually non-cylindircal.. lumpy).
Follow Phytech's advice... ohm it out with a multimeter.


**broken link removed**

 

[lee321987]

It measures ~1ohm -- as the box they were in was labeled, but I can't find anything on the web that describes a wider band on the left side of a resistor. I also can't find anything color code table that allows a silver first band.
I did find a page that mentioned an inductor having a wide band on the left, calling it the "military identifier" band, but nothing for a resistor.

 

[KJ6EAD]

10µH 10% inductor. Pronine Electronics Design - Inductor Color Code

 

[lee321987]

If it were an inductor, would it still measure 1ohm on my multimeter?
I guess I should mention that I'm using a cheap multimeter and it's lowest ohm scale is 200ohm, however I tested a few for-sure inductors, and they measure a short on ohm meter.
Is there some circuit I can build to test them, or maybe if I just cut one open, can I tell from what's inside?

[EDIT] I broke one open (pic attached) and you were right -- it's an inductor (red coil of wire).

Still – I'd like to know if there is a simple circuit to test.

 

[enjunear]

If it were an inductor, would it still measure 1ohm on my multimeter?
I guess I should mention that I'm using a cheap multimeter and it's lowest ohm scale is 200ohm, however I tested a few for-sure inductors, and they measure a short on ohm meter.
Is there some circuit I can build to test them, or maybe if I just cut one open, can I tell from what's inside?

[EDIT] I broke one open (pic attached) and you were right -- it's an inductor (red coil of wire).

Still – I'd like to know if there is a simple circuit to test.

If your ohmmeter isn't very high resolution, then I'd imagine your lowest number the display has is either 0 or 1 ohm. If the resistance of a part is 0.4 ohms, then I'd think the meter would round that down to 0 ohms. If the part measured was 0.6 ohms, then I'd think it would round that up to 1 ohm.

A wire-wound inductor is just a long piece of wire, and that wire has a certain resistance, per unit of length. If you have a long enough piece of wire, you can develop a couple ohms of resistance, easily. There is no such thing as zero resistance, at least in the world most of us work in.

You could more accurately test the resistance of the part by running a known current through it, and measuring the voltage drop across it (probably in the mV range). Example, run 300 mA through it, measure 250mV drop, then R = V/I = 0.25/0.3 = 0.83 ohms.

 

[Phytech]

The color code reading looks like 10 (brown, black, black) with tolerance of +/- 10%, it doesn't mach what you measured 1 ohm value. So it is more like an inductor than a resistor. There are also wire wound resistors which you can find from Resistor - Wikipedia, the free encyclopedia.

 

[KJ6EAD]

There is a simple method to measure the inductance using a power transformer and the power line frequency. This is covered in most AC electronics study materials as an experiment.

 

[chuckey]

I would go for using one of the silver bands as a .01 multiplier, so its one ohm, +-10%. Googling "resistor colour code" results in loads of picture, however none have a silver band as the leading band, could this be a Chinese resistor?
Frank

 

[lee321987]

It's an inductor with a military color band (the wide silver band).