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Post by sumgai on Jul 18, 2017 16:53:33 GMT -5
Found this courtesy of HardOCP, a site that does RSS feed into my third most read site, dailyrotation.com (the second being techdirt.com, and you can guess which come first....).
It's a video on a cheap DMM from a site heretofore unkown do me, banggood.com.com. Might be of interest to some readers who can't/don't want to lay out big bucks for something they'll use only occasionally. Can't say as I blame them, the big names aren't cheap. But this one that was purchased and tested (for about 20 minutes!) seems to be quite acceptable for hobby purposes.
www.hardocp.com/news/2017/07/17/cheapest_multimeter_on_banggood/
HTH
sumgai
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Post by reTrEaD on Jul 20, 2017 9:28:19 GMT -5
I have several of these. Or something that appears to be the same but with a different brand name. www.harborfreight.com/7-function-multimeter-98025.htmlEasily worth the five or six bucks if you have to buy one. But I got mine free with coupons. Just had to buy anything else from HF to get the meter. Even if you have a great meter like a Fluke 8060A or a Keithley, you'll want at least one of these for use in rough environments. They're lightweight so they survive most of the time if they fall off the workbench onto the concrete garage floor. And you won't lose any sleep if you smudge them with greasy hands. One thing I don't like about these meters is that you have to remove a few screws to replace the battery. But since battery replacement is rather seldom, it's not that big of a problem.
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Post by JohnH on Jul 20, 2017 16:46:29 GMT -5
That red one, usually in yellow, seems to be this planets generic cheapo DMM. Here we can usually buy them for about $10 to $15 AU. Ive had two of them and they cover all the most useful things with adequate accuracy. They do a few extras too. You can with care, use them for phase tests on pickups. And if you are into active circuits, they will help sort out random transistors for type, pin-out and gain.
They tend to blow out if you run too much current through them. Also, batteries need to be reasonably fresh since results tend to wonder off into inaccuracy, while still giving an apparently clear display; if the battsry is low.
For my meter currently, I splashed out $50 for one than also does L and C measurements. I didnt expect too much but Im very impressed with these features at this price. Known components measure within tbeir spec, including 1% resistors and 5% caps. Pickup inductances are close to spec for a couple tbat actually have specs. It seems to do these tests using about a 100hz signal.
Apart from sorting pickup charactetistics, tone caps etc, it is just sensitive enough to compare cable capacitance on a 20nF range. For this, the last two digits can tell you which is the lowest capacitance. Id be unsure of absolute accuracy there but I think it is ok and useful for comparison.
One meter Id love to get hold of is an old brick-solid, brick-heavy, shoe-box sized analogue Avometer, like we had at school in the '70's.
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Post by b4nj0 on Jul 20, 2017 17:03:46 GMT -5
You mean an AVO 8 John? You can bang a nail in with one (well not literally!). I have two. Well actually, one is the mil-spec variant known as Multi Meter Mk. 1 but it's the same beast in an additional metal casing.
Remember that they are only 20K per volt which is OK under most circumstances but you do need to be aware of the circuit being loaded occasionally and make appropriate allowance(s).
It's a shame you're down under because otherwise I'd sort you the non mil-spec one I have. (I'd have to find the wee beasty too- easier said than done!)
Finally, don't forget that weird 15 volt battery...bet you can buy them anywhere? maybe not such a great idea after all?
e&oe...
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Post by JohnH on Jul 20, 2017 17:16:23 GMT -5
Thanks for that thought b4nj0. Its a nostalgic wish really. I dont know the model we had, but I'd recognise it if I saw one. It would bring back some happy Saturday afternoons, like the smell of burnt-fingers with hot solder!
I didnt know they ran on 15V though - I never went inside.
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Post by b4nj0 on Jul 21, 2017 1:43:49 GMT -5
That's because the battery lasts for years, but when it's dead- it's gone. That would not stop the likes of us though would it? Sadly, as good as an AVO 8 is, a 5 dollar DVM won't load a circuit under test in the same way because of the very much higher ohms per volt rating. As with all things having a digital read out, numbers of digits on the display should not be taken as an indicator of high(er) accuracy. Best not to confuse resolution with accuracy. I purchased one of these little multi testers on eBay: m.ebay.co.uk/itm/2016-Transistor-Tester-TFT-Diode-Triode-Capacitance-Meter-LCR-ESR-NPN-PNP-MOSFET-/272671833854?nav=WATCHING_ACTIVEIt came from China and they can be purchased for less outlay now. I bought one ready installed in a plastic case with an LCD read out like the one in the link.It has a Li-Ion rechargeable and a ZIF socket. I have been amazed by what it does. Stick a transistor in and it identifies PNP or NPN and tells you which leg is which! I haven't checked the accuracy, but have had great fun measuring audio output transformers and other inductors like pick ups! It even has an IR decoder! You can purchase just the populated PCB, but I have too many unfinished projects laying around. e&oe...
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Post by reTrEaD on Jul 21, 2017 12:16:30 GMT -5
That red one, usually in yellow, seems to be this planets generic cheapo DMM. Yes, more often in yellow, sometimes in red or black. Also, there's a sister to it which doesn't have a separate on-off switch. Instead, the selector has a an off position at the top. The case is virtually identical with the exception of the switch and color of plastic. I would guess these all come down the same production line with different brand names applied. Just for shitsandgiggles I looked around on one of antigua's frequently used sources, Aliexpress.com Under three bucks US with free shipping. But it's China Post so figure about a month to the US. Maybe a bit longer to other countries. www.aliexpress.com/item/Professional-Digital-Multimeter-DT830B-AC-DC-Ammeter-Voltmeter-Ohm-Electrical-Tester-Meter/32799292275.html
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