Forgot how to calibrate my multimeter -oops!

[fnqcairns]

Can anyone remind me what ohms setting (1K?) I need to use on my analogue multi?

I almost bought a new battery today because of an incorrect reading - till I twigged.

thanks fnq

[-Scott-]

I'm not sure what you're trying to do. What are you trying to measure?

Scott

[fnqcairns]

G'Day Scott, I am trying to 0 zero the meter for measurement. In the past I used to select the proper ohms reading, touch the two electrodes then with a knob align the needle at the proper 0 ohms reading. If this is not done then even dc current reading can be out and by a long way although I can use any ohms setting but only one is correct and they each give differing readouts when back on a DC setting.
Only one is correct and I forget which

Yesterday I forgot which was my coffee cup for the last 2 months but my 2 year old was able to tell me, it's getting to be a worry

Cheers fnq

[DamTriton]

Put the leads together (short circuit) and use the knob to adjust the needle for "0 Ohm" at the far right hand side of the meter scale.

[-Scott-]

The analogue meter is actually a milliamp meter, which displays the number of milliamps flowing through the coil in the meter. The different "ranges" are selecting different circuits, to "condition" what you're measuring into milliamps, so you can read it from the scale. This is why you have different scales on the meter display - all the different measuring ranges apply different factors.

When you measure resistance, your meter is trying to make current flow through the external circuit - which is why zero on the ohms scales is at the opposite end, because your meter is actually injecting maximum possible current.

Zeroing your meter for resistance readings is compensating for the resistance of the leads and the connections. Since it should all be significantly less than 1 ohm it shouldn't be significant for higher resistance readings, but you can still go through the same process - as Gary said.

Zero on voltage and current readings should be zero regardless - if there is no energy in the circuit, there's nothing to measure. I'm not sure how your zero ohms adjustment is affecting your DC readings - so I guess I've just typed a lot of stuff to say I can't help you.

I love digital multimeters - just read the number, and try not to think about it.

Scott

[fnqcairns]

Ok thanks Damkia, I worked out what was going on, for some reason each time I 0'd it then upon returning to the same ohms scale I would need to re 0 again, so I spent a couple of minutes turning the ohm adjust knob back and forth and now it works (must have been a poor contact) like I remember it should . Now I am getting the same reading on dc now no matter which resistance setting I zero at which helps alot

I had better keep an eye on it in the future, not going senile yet!

cheers fnq

[fnqcairns]

Good info Scott for somene like me who only knows what he needs to get by in electrics.

I too would like a digital one, this one cost over $100, 10 years ago from memory so until it shit's it's self good and proper I will stay stuck to it .

cheers fnq

[DamTriton]

Good info Scott for somene like me who only knows what he needs to get by in electrics.

I too would like a digital one, this one cost over $100, 10 years ago from memory so until it shit's it's self good and proper I will stay stuck to it .

cheers fnq

<$25 from Kmart for a digital multimeter.

[ausoops]

is it an avo? if it is ill buy it off you