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# How to measure an unknown resistor?

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#### Screech

##### New Member
How to measure an unknown resistor?
Whats the correct and safe-to-multimeter way to do this?

Do I set the electronic multimeter to 2meg first, then work my way down the ranges? Or is it the other way?

Also, can I damage the multimeter when measuring an unknown 4.7Meg resistor when setting the meter at 2Meg range?

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Hello Screech

You can use it both ways.. there is no posibillity to damage the resistor or the multimeter... just connect the resistor and play with the scale.

Will do.
Thanks Mixos.

checking unknown resistance

hi screech,

just make sure that when you measure the resistance the power supply is OFF. :wink:

Damn! It would be good if I could do it with the power on. OH,well. :?

checking resistance

hi screech,

if a meter can be invented to measure a resistor resistance while the power is on in the circuit, that person will be an instant billionaire. 8) :lol: :lol:

forgetfulness is inherent to mankind :wink:

Re: checking resistance

mozikluv said:
if a meter can be invented to measure a resistor resistance while the power is on in the circuit, that person will be an instant billionaire. 8) :lol: :lol:

Use a combination of a Clamp meter (to measure the current trough the resistor) and a Volt meter (to measure the voltage drop accross the resistor), and you can calculate the resistance ...

...Am I a billionaire now ? ... where's that porche

If you'll use the ohmeter to mesure the resistance, take the resistor out of the circuit and measure it... Some of the circuit components may affect resistance...

to measure a 4,7Mohm with a a ohm-meter at 2Mohm range.. do this.. use a 1Mohm resistor

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It would be good if you set the multimeter to the high value of resistance and then start reducing it when you see the symbol "l" in the multimeter.That symbol indicates that you have chosen wrong range for the resistance.

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