# What is the name of the device used to measure ohms?

1. Mar 5, 2005

### Geoffrey F. Miller

What is the name of the device used to measure ohms?

2. Mar 5, 2005

### dextercioby

With a multimeter,you can measure both tension & current,ergo determine resistence...

Daniel.

EDIT:I suspect a tool only for resistence would be called OHMMETER...

3. Mar 5, 2005

### Geoffrey F. Miller

I need to be sure that it's called an ohmmeter though. I don't want to introduce to many calculations into my experiment, as it's only supposed to focus on how a wire's length, shape, mass, thickness, and material affect its resistance.

4. Mar 5, 2005

### dextercioby

It's not too many calculations,just a division V/I.In case you lack the ohmmeter.

$$R=\rho\frac{l}{S}$$

Is this what you're looking for...?

Daniel.

5. Mar 5, 2005

### dextercioby

Oh,and one more thing:I'm pretty sure that the ohmmeter used Ohm's law (!) to determine the resistance and doing that by performing the division,insted of you...

Daniel.

6. Mar 5, 2005

### Geoffrey F. Miller

Ahhh...I found an ohmmeter, and yes, it does use Ohm's Law.

Also, do you know how a wire's mass would affect its resistance? I'd assume more massive wires would be less resistant...

7. Mar 5, 2005

### dextercioby

No,not directly.The ratio is (length/area) (times resistivity,see above).So mass is involved indirectly.

Daniel.

8. Mar 5, 2005

### Geoffrey F. Miller

Okay. Also, why do electrons move faster and more effeciently through metals than nonmetals? What are the characteristics of a good conductor? Does it have something to do with the way the atoms or molecules of a substance are arranged?

9. Mar 5, 2005

### dextercioby

Of course.Internal structure is the key...Quantum Mechanics and Transport Phenomena give all the answers/explanations.

Daniel.

10. Mar 5, 2005

### Geoffrey F. Miller

One more thing before I go, does the ohmmeter require electricity to be running through a wire to take its measurements, or does it test the material directly?

11. Mar 5, 2005

### Integral

Staff Emeritus
Yes, an ohmmeter must be powered.