Decent Digital Multimeter for DIY?

:) Are you unfamiliar with how multimeters can kill people?

NT

Reply to
tabbypurr
Loading thread data ...

All too familiar which is why I won't use one on mains. ;-) There are far better designed devices designed specifically for this job.

Reply to
Dave Plowman (News)

Last week I picked up a used but in perfect condition high voltage probe made by AVO. When used in conjunction with my good 'ol British AVO

***ANALOGUE*** meter, I can now measure voltages of up to 32kV. :) Try doing that with one of your BnQ ten quid specials. :)
Reply to
Cursitor Doom

Pretty useless for measuring things like CRT HT, though. Input impedance is too low. A similar probe on a 2 quid DVM will be fine. ;-)

Reply to
Dave Plowman (News)

that's easy. string of 3w resistors, bit of coathanger, bit of polystyrene. BTDT.

NT

Reply to
tabbypurr

3 watt resistors?? Hmmmm.....And what grade of polystyrene would that be? I'm sure you know exactly what you're doing, though. ;)
Reply to
Cursitor Doom

Yup, theyre long enough to have a useful voltage rating

any grade, its not specced for electrical insulation

I included a ground shield in the styrene so that if it fails for any reason it arcs to ground, not to the user. And naturally HV kit needs testing before use.

NT

Reply to
tabbypurr

Yeah, go pick on something that has like microscopic source impedance why don'tcha? Please note: I still keep a couple of DVMs and the really important thing is the ***PROBE*** - and having the balls to use it at 32kV (which TBH I must admit I don't have). But it is *well* out of DIY range, let's face it.

Reply to
Cursitor Doom

Ahh. I see. Makes sense in a 'get-you-home' sort of way.

No kidding? :-D

I'm sure readers will be reassured to know it only starts fires rather than electrocutes the homeowner.

Just discovered another meter in my possession (a Taylor Instruments) dating back to around 1960 that has a *basic* 2.5kV measurement capability at 20kopv, giving me the capability to measure EMFs up to 75kV if I can obtain an even higher rated 30x EHT probe - yeah, baby, yeah!

Reply to
Cursitor Doom

At one time measuring CRT HT would have been DIY for those who fixed or built tellies. I had a Heathkit valve voltmeter (with HT probe) for that job. Still got it. But it doesn't get used these days - any more than the AVO 8. ;-)

Reply to
Dave Plowman (News)

Is there anything that most all of us would need to measure up there at that voltage, seeing that CRT's are almost extinct now?...

Reply to
tony sayer

No, it makes sense in a basic electrical engineering kinda way. Long resistors tend to have higher voltage specs.

nope

why would it start a fire? You seem to be missing the basic engineering behind this completely.

upto anything at all if it has enough current delivery. 20 k per v is too often too low of course.

NT

Reply to
tabbypurr

There never was, for most people. For electronic folk there's still microwave ovens, occasional HV power transmission, vintage tv, and other occasional/extreme projects. DIY x-rays anyone?

NT

Reply to
tabbypurr

Looking on YT I see quite a lot of nuts who are into indoor lightning. If you want to mess around with tesla coils and Cockroft-Walton multipliers,

32kV is nowhere near enough!
Reply to
Cursitor Doom

Sorry, I meant *huge* Zs, not "microscopic" - D'oh!

Reply to
Cursitor Doom

Yep, but do you measure those sort of voltages perhaps you know that a spark "x" of such a length is equal to "y" volts;?..

Reply to
tony sayer

Do go on...?

Reply to
Adrian

Arc flash. Circuits after a CU's fuses don't deliver enough current for long enough to cause an explosion, further upstream they surely can.

NT

Reply to
tabbypurr

Yes, that's how a lot of these kind of measurements are carried out - in dry air of course.

Reply to
Cursitor Doom

Well you can't really blame me. Your description is a bit vague, after all: "string of 3w resistors, bit of coathanger, bit of polystyrene." "Engineering" seems rather a grand term for such a sloppy sounding lash- up. :)

It was the 'gold standard' 50 years ago when this meter was made! Anyhoo, as I said I keep a couple of modern DVMs with much higher input impedances so if lack of grunt on the part of the DUT is a problem I can just use one of them.

Reply to
Cursitor Doom

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.