I need multimeter help!!!

[LettucePrey]

Ok, So I just picked this multimeter up at harbor freight for $4 and am trying to figure out how to use it to aid in my pedal builds.

First off, here is the multimeter:



I've been able to get readings for transistors, resistors & diodes using the various settings but can't figure out how to get it to read capacitors of any type.

I'd also like to be able to connect the leads to the ends of a component and see if it is actually working (continuity?). Can this be done with this multimeter?

Any info would be great!

[Vince]

http://www.youtube.com/watch?v=FDuN7QHn1-s

[Surgeon]

Otherwise than testing whether it's open or not, you won't be able to test capacitance on a regular dmm.

I found a very cheap (13$ or so) capacitance meter on ebay ( from china of course) and it works perfectly.  You should definitely get one if you intend to really test capacitors ade quately...

[GoranP]

Why wouldn't he be able to test his capacitors with this DMM?
It may not be the most accurate measurement in the world but I doubt it's miles off your chinese meter.
If the battery is not empty it should measure just fine. The manual probably indicates the error margin and the caps themselves mostly have very wide tolerances.

[JaviCAP]

Goran, this MM has no capacitance meter, you can't measure any capacitor, except as previously said, testing if is open or woking ok.

This is one of my MMs (I have about 6 different ones), and I can tell it for sure. It has no continuity test / beeper neither and the diode probe is < 1volt, so of no use with leds

By the way, is a ridiculous dirty cheap MM, and the resistance,dc, ac, dca  and HFE measures are very accurate but you can't ask for more for this money.

BR

[Silver Blues]

@Javi lol, this sounds like a really kind of shit meter if it doesn't even have a continuity tester  that's a must-have feature, especially if you do more than just pedals.

@ Surgeon the meter I've got tests caps. It's pretty damn accurate too.

[JaviCAP]

Yeah, is a shitty meter, but what more  can you ask for 2.95 euros in a chinese bazar? :P I always use  to have some mm of this kind, to avoid puttin in risk the good ones. If something has to be blown, better be this crap :P

[GoranP]

Oh, my mistake... i saw the u(micro) sign and assumed it's a capacitance test when in fact it clearly states "DCA" for current testing. D'oh!

And nonexistant continuity testing is definitely a dealbreaker, no matter how cheap it may be. It's interesting that it has a hfe measurement, it's usually missing on dmms many times the price. It being accurate is also a surprise :)

As for using it for anything iffy, I'd rather have the most expensive one I have be between me and the risky place. I just feel more protected if the tool is a quality one and not a questionable piece of plastic. I doubt this one has a fuse in it?

[Surgeon]

Goran: My point is that if you look closely at his DMM (I'm here assuming that the DMM pictured is the one he bought), you can see that it doesn't have capacitance measure capability...hence he can't do anything else than verify if it's open or not... I bet my cheap chinese one is much better than just verifying open or not capacitors.

Silver: good for you. As stated above, I was strictly pointing out that the meter pictured in the thread did not have that capability.

[LettucePrey]

So...I CAN'T measure capacitance with this but I CAN verify if a capacitor is open or not. What exactly does being open mean (in relation to components )

My reasoning behind all of this is that I built the super simple em drive and I'm positive everything is correct as I've looked it over at least 100 times. I bought some of the mojo vintage russian K42Y-2 caps off ebay and I'd just like to see if they are to blame for the circuit not working.

[Silver Blues]

Surgeon wrote

Silver: good for you. As stated above, I was strictly pointing out that the meter pictured in the thread did not have that capability.

My bad, I must have read that wrong.

[Surgeon]

I've used this procedure before I bought my cheap capacitance meter. it works but with a digital screen, you have to pay close attention, especially with smaller values.
I'm too lazy to type it anyways so here it is, copy-pasted from an ebay guide:

1) Discharge the capacitor by shortening its leads. that is - use a wire and connect the leads of the capacitor together. this will discharge it.

2) Put your multimeter in the high ranges 10k-1m

3) Connect multimeter to capacitor leads(observe the polarity if electrolytic). at soon as the leads make contact, the meter will swing near zero. it will then move slowly toward infinity. finally the meter would come to be infinite ohms because the capacitor is being charged by the battery of the multimeter.

4) If the capacitor is bad, it will go to zero ohms and remain there. this is called a shortened capacitor

5) In the case of an open capacitor there will be no ohmmeter indication.

6) Some capacitors have a low dielectric leakage. you will know this if the ohmmeter comes to rest at a point lower than infinite. test a known good capacitor of the same type to be sure.

PS: This test works for large capacitors. Tiny capacitors can only be checked with a capacitance meter, or by using them in an AC circuit and checking for variation from calculated voltage drop.

[GoranP]

Surgeon wrote

Goran: My point is that if you look closely at his DMM (I'm here assuming that the DMM pictured is the one he bought), you can see that it doesn't have capacitance measure capability...hence he can't do anything else than verify if it's open or not... I bet my cheap chinese one is much better than just verifying open or not capacitors.

That's right. We are in agreement, it was a wrong assumption on my part that it does measure capacitance simply because I noticed a micro(u) sign. After a closer look, I realized that it's a current measurement, not capacity.

I think we can all agree that a buck or two more could have gotten the OP a meter with all the basic operations he might need.
I still wouldn't be poking around a tube amp with this.

Also, good stuff on cap measuring!

[LettucePrey]

Ok, to make this easy....From the 2 links below, which of the following (if any) will do everything I need?

Preferred (I live near this store)

Any of these?

[GoranP]

Well the first one pretty much does it all, my only concern is how accurate it is in the picofarad range (because it has no explicit picofarad range and is apparently classified as anything <2nF). It's probably fine, especially for the price.

Most of the dmms on the second link don't even have capacity measurement and those that do are autoranging (again, range not specified) kind.
I don't particularly care for autoranging stuff as in my (somewhat limited, never had an autoranging Fluke) it tends to be slower to get a reading.

EDIT: ok, the fancy manual states that in 2nF range the resolution is 1pF with 4% error. I can live with that for $20

[Beaker]

Yeah that first one seems to tick most most boxes. Shame the lowes site does not seem to display prices - makes comparison kind of hard!

I have to say I own several meters, and each have their merits.

In fact my go-to is a cheap pocket auto ranger with no HFE or cap test facility. The reason it is my go-to is because it is far and away the best continuity meter I have - really loud and clear, and I love being able to double check resistors and pots with it without fiddling with the range knob all the time.

I swear by my analog needle dial multimeter when working on guitar pickups - way better than a digital.

No need to spend too much - spend your money on pedal parts and components instead!