nice DVM

Maybe they mean not for household use. Household use could invoke extra regulation and liabilities.

I use mine at home! Every home need a good DVM and a thermocouple probe and a bench power supply.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

Oh no, I'm well aware of the "I used this meter on the current range to check my 13 Amp mains points" etc.

I was wondering what job the word "domestic" was really *doing* in that sentence. "Domestic" means "in the home", or possible an alternate word for a cleaner/servant.

If they mean "not for use by end consumers or idiots", "only for use by trained expers" etc. then they should write that.

People will still ignore it, but then they have actually attempted to clearly cover themselves.

As written, it could mean "Can be used in the pouring rain outside", for example. "Can be used by idiots, but not by their cleaner", which is mad. "Must not be used by a trained engineer inside a home" ...

If that's the case (and I agree, that would be the number one reason), the wording really should be clearer to say what it

*means*. e.g. the "DO NOT DISASSEMBLE" and "NO USER SERVICEABLE PARTS" standard warnings! :)

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--------------------------------------+------------------------------------ 
Mike Brown: mjb[-at-]signal11.org.uk  |    http://www.signal11.org.uk

No doubt you can use a meter, mostly. Granted, that board looks ok and it has the usual good quality fuses you'd see in the rest of the Fluke lineup.

I recently had to call up Fluke to ask the difference between one instrument and the II version. It turns out nothing at all except one agency rating which was added with no changes needed to the instrument itself. Yeah, the price is a bit higher on ebay for the "new" versions.

Recently pickup up a fluke clamp type meter. It seems pretty dumbed down for most part and seems to have a decent safety factor in that it completely lacks an current range. You just can't blow the thing up in bad range or lead connection. Fits in a zipper tool bag or tool box too.

----------------

** Not a hazard at all, it trips the circuit breaker.

** Wrong again - it refers to use by untrained persons. The term is commonly seen in *electrical regulations*. Non standard AC power connectors like the PowerCon are excluded by it. ** Bit of a mouthful and very insulting. ** It called a "disclaimer".

** You need help with the English language. ** Electrical test equipment is not covered by domestic appliance rules, cos they make such gear impossible to use. You need to do some more thinking.

..... Phil

You are overlooking the second most common meaning of 'domestic'.

2 : of, relating to, or originating within a country and especially one's own country

It is a 'lawyer' way of saying: "Not for use in the USA".

If you are measuring something with a high peak to average ratio, the internal power dissipation might kill the instrument,

Assuming the instrument is set to 600 V but the input contains 6 kV peaks with 10% duty cycle then even a simple analog meter would average that to 600 V. An uneducated person may think that is OK and let the instrument be connected for a long time.

However, the internal peak power dissipation is voltage squared (100x) and with the 10 % duty cycle, the internal average power dissipation is 10 times the value, compared to the dissipation of a steady state

600 V source,

I think the meaning is, if you put it on current mode and plug one probe into the wall socket, and touch the other probe, you've technically done something stupid, that a homebody might not know WAS stupid. It's a liability thing. In court, afterward, explaining: that was an instruction for use (i.e. don't use it if you aren't savvy about electricity) that the user disregarded.

I can only loan out my Fluke meter; my other meters don't burn out fuses, they burn up, but the Fluke comes back intact (at the cost of a fuse, at worst).

's of

I had a Fluke 87 that started tearing through batteries (9 V, in this case) . I fixed it by taking apart the main selector switch and cleaning the con tacts. It turns out the carbon traces get smeared together and start condu cting across channels, draining the battery. I cleaned up the pads where t he display's zebra strips mounted, and the display looks better now too. T hat Fluke 87 has been my main workhorse DVM for 2 decades.

ditto.... Bench supply should be tri voltage, have CV and CC modes, and I'd include a AC/DC current clamp, & HV probe to go along with the fluke DMM, and isolation transformer/variac. (I'd also add a good scope, spectrum analyzer, logic analyzer and a assortment of tek tm5xx modules....then again, my home is my lab....)

Three Jeeps wrote: =================

** I do repair and design of pro audio products, since 1980.

On my bench are are:

2/20 amp 3.5digit, RMS current monitor Tenma 0-30V @3A digital variable

-15V & +15V fixed, 2 off 2-20V 2A ,

1.2-12V @5A, +/-100V @0.25A variable, 4amp, 0-260V Variac, 2 off 7 digit frequency counters, 2Hz to 200kHz low THD generator. 50MHz dual trace scope. LED 4.5 digit DC & 100kHz true RMS meter Keysight 6000 count DMM Digital ESR meter Hakko FX888

Plus:

2 x 3.5 digit DMMs 35MHz dual trace scope. 10MHz single trace scope Tube audio generator, 20 to 20KHz. Pink / white noise generator 3 spot, -100dB notch filter 20-22KHz audio band filter Mic pre-amp with headphone output. Power BJT Hfe tester K-type thermocouple adaptor Quad 15W tube amp and 12" speaker

..... Phil

I don't do electronics at home, but a power supply is handy for testing things, charging a dead car, all sorts of stuff. It needn't be fancy, just 0-24 volts at 1 amp maybe, with voltage/current display.

Some "modern" car battery chargers won't even try to charge a flat battery. A DC power supply does.

The DVM should have a thermocouple input and a needle probe for checking meat internal temperature.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

On 7.1.21 7.58, snipped-for-privacy@highlandsniptechnology.com wrote: home is my lab....)

Please be aware that many lab supplies turn belly up if there is a car battery connected at the output without any input to the supply.

In the cold winters in the 1980's (below -30 degrees C), more than one of our lab supplies died with careless car battery charging.

--

-TV

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** Only takes *one reverse connected diode* across the regulating transistor to fix that.

Standard practice in any general purpose PSU for decades.

..... Phil

I killed one of my lab supplies the same way. Connected the output to the battery before turning it on. The battery may not have enough juice to turn the engine over, but it sure has enough to ruin the supply.

Probably be a good idea to get a cheap battery charger for car batteries. It doesn't have to be a fancy one with all the bells and whistles.

If you shop around you can probably find a cheap transformer/rectifier unit for $30 or so, or even make one from parts in your junk box. The hardest part is getting the battery clips.

--
The best designs occur in the theta state. - sw

Everybody has a stash of banana leads and alligator clips and resistors and diodes at home, don't they?

I once started a dead car using 120 VAC and a diode and a heat gun as the current limiter. Might not have needed the diode.

Perhaps, though there are some crappy designs out there.

I would expect that connecting the battery backwards would be a more common cause of destruction. Only something designed specifically as a battery charger is likely to include protection against that situation.

The default behaviour of Keithley Sourcemeters is to short-circuit the output terminals when the output is turned off. There is a warning about that in the manual but I expect that a few have been fried that way when used for charging batteries.

I bought a Keithley SMU and sent it back. It was fantastically RFI sensitive.

This is set for 10 volts out, and that's my hand grabbing the leads.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

** He says, clutching at straws.

If it ain't got one - add one.

** They have series diodes, but a parallel one on the output of a PSU works well too.

............ Phil

The lead-acid charger I took apart had rather more elaborate protection. A series diode doesn't help against a (partially charged) battery connected backwards, though it might help against a battery connected the right way round, with the mains off, (if that was a problem in the first place for that PSU). A parallel diode only helps if there is a fuse or circuit breaker between it and the battery, of course.