I'm DMM Deficient
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- Kwote
- Voltage Controlled Crackpot
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- Joined: Fri Oct 26, 2007 3:24 pm
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I'm DMM Deficient
that's right. i'm a retard when it comes to using the DMM.
somebody help me!
i can build the kits but to be honest i never really tested or calibrated. just plugged and prayed. it's worked out but i can't keep this up.
i sorta got the basic concept figured out but i can't seem to get accurate readings.
in short: goddammit.
somebody help me!
i can build the kits but to be honest i never really tested or calibrated. just plugged and prayed. it's worked out but i can't keep this up.
i sorta got the basic concept figured out but i can't seem to get accurate readings.
in short: goddammit.
- Muff Wiggler
- wait, what?
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- Joined: Fri Nov 24, 2006 12:19 pm
what's the trouble? I have a $9 DMM I got at Radio Shack, pretty easy to use. Select the type of stuff you want to measure, and the range of the value you expect to see, using the big dial.
Two leads come from it. You touch (and hold) one to ground somewhere, and then touch the other to the point on the board you need to measure, or the calibration point. See the value on the screen.
That's for most measurements. For current draw, you basically cut the power cable, put the DMM in between in, one lead towards the power supply, one towards the load (module).
Perhaps you aren't grounding it when measuring at a calibration point?
Two leads come from it. You touch (and hold) one to ground somewhere, and then touch the other to the point on the board you need to measure, or the calibration point. See the value on the screen.
That's for most measurements. For current draw, you basically cut the power cable, put the DMM in between in, one lead towards the power supply, one towards the load (module).
Perhaps you aren't grounding it when measuring at a calibration point?
- Muff Wiggler
- wait, what?
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- Joined: Fri Nov 24, 2006 12:19 pm
are you testing at TP1 or testing at the trimmer? the RT1 trimmer sets the amplitude..... you measure it at TP1 though.
One probe on TP1, one probe at common. If your DMM doesn't auto-switch, then make sure it's the ground probe that goes to common.
Also, make sure you set your DMM to the right range. You should set it for '1V' (or as close as you can, maybe 2V or 5V is the best choice).
hope this helps!
One probe on TP1, one probe at common. If your DMM doesn't auto-switch, then make sure it's the ground probe that goes to common.
Also, make sure you set your DMM to the right range. You should set it for '1V' (or as close as you can, maybe 2V or 5V is the best choice).
hope this helps!
- Kwote
- Voltage Controlled Crackpot
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- Joined: Fri Oct 26, 2007 3:24 pm
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i think i'm gonna chalk it up to having a shitty dmm.
i'm gonna buy a cheaper bulkier one with a meter instead of a lcd display and see if it's more dependable. fuckin radioshack givin me headaches.
i think i got within the ballpark for everything though but this fuckin thing ain't consistent at all.
i'm gonna buy a cheaper bulkier one with a meter instead of a lcd display and see if it's more dependable. fuckin radioshack givin me headaches.
i think i got within the ballpark for everything though but this fuckin thing ain't consistent at all.
- Muff Wiggler
- wait, what?
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- Joined: Fri Nov 24, 2006 12:19 pm
- Muff Wiggler
- wait, what?
- Posts: 7815
- Joined: Fri Nov 24, 2006 12:19 pm
- Kwote
- Voltage Controlled Crackpot
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- Joined: Fri Oct 26, 2007 3:24 pm
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yeah. sorry my mind was off. i just meant one with a dial for selecting the settings i want.Muff Wiggler wrote:Oh yeah - don't buy a MM with a needle meter. Buy one with an LCD. Kinda hard to fine-tune something to 0.644v or whatever using a needle meter.
the problem with the radioshack one is i have to scan through with a button and it only brings up 3 choices in the Volt section even though the manual suggests there should be more.
atleast the ones with the dial have a bunch of in your face options and i can go right where i need to go. 2v for the +15/-15 reading and 600v for the .644 reading.
just mad cuz i spent 30 bucks on that stupid radioshack one thinking it would be nice to have something compact .

the new filter works just as great as the last one so i don't think there's anything wonky but i'll test the other just to be extra sure.
thanks man.
- futuresoundsystems
- <3 CMOS
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...get an analogue one....
Seriously, I find I use my trusty, "non-powered" analogue multimeter more than my digital. The DMM I have often gives wonky results, sometimes very correct, others all over the place. I always check it with the analogue just in case.
Seriously, I find I use my trusty, "non-powered" analogue multimeter more than my digital. The DMM I have often gives wonky results, sometimes very correct, others all over the place. I always check it with the analogue just in case.
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- Kwote
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hmmm. yeah. not a bad thought. i'll get a cheap one of both and contrast/ compare.futuresoundsystems wrote:...get an analogue one....
Seriously, I find I use my trusty, "non-powered" analogue multimeter more than my digital. The DMM I have often gives wonky results, sometimes very correct, others all over the place. I always check it with the analogue just in case.
- Cat-A-Tonic
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Mine is an AND AD-5528
It has the LCD readout and the big dial with ohms. volts, and amperes.
I think it cost me about $40.
It is very portable and really accurate.
It is more accurate than my father in law's DMM's and he was an electrical engineer.
Sometimes a point will fluctuate in voltage if there is another spot that needs to be trimmed first.
Fiddle with the trimmers a bit more and you may be able to tame it.
It has the LCD readout and the big dial with ohms. volts, and amperes.
I think it cost me about $40.
It is very portable and really accurate.
It is more accurate than my father in law's DMM's and he was an electrical engineer.
Sometimes a point will fluctuate in voltage if there is another spot that needs to be trimmed first.
Fiddle with the trimmers a bit more and you may be able to tame it.
I'd say have both.
I generally used my analog one for everything (until it broke) but the circuit short indicator ("beep") on the DMM was indispensable for debugging why a circuit wasn't working.
I generally used my analog one for everything (until it broke) but the circuit short indicator ("beep") on the DMM was indispensable for debugging why a circuit wasn't working.
dress yourself for the public. you now must exit your home and acquire a dental mirror and lubrication!
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i recommend a hat, or a helmet. if a helmet, ensure that it is both convincing and unbiased. -citizen mori
https://www.modulargrid.net/e/racks/view/78959
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https://jimdrones.bandcamp.com
A DMM is one thing you would want to invest in if you're doing DIY.
It's invaluable in making sure that what you built is actually up to spec.
I found the cheapest FLUKE off ebay and never look back. It is rock solid and stable and always a consistent measurement device.
It also helps you trace built errors, test resistor values (instead of reading their colors), measure up capacitors, test LEDs etc.
It's invaluable in making sure that what you built is actually up to spec.
I found the cheapest FLUKE off ebay and never look back. It is rock solid and stable and always a consistent measurement device.
It also helps you trace built errors, test resistor values (instead of reading their colors), measure up capacitors, test LEDs etc.
Erez Yaary
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Home Page: http://www.yaary.com
Facebook: http://www.facebook.com/erezyaarymusic
Buy my CDs at http://www.mellowjet.de