Maplin Multimeter: how to use?

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would
Commercial ductwork has temp sensing holes to insert the temp probes.
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Have a look at
http://www.tmelectronics.co.uk/hheldair.html
These are the ones that RS sells but I believe the manufacturer sells direct as well.

.andy
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go
the
Thanks.
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writes

If you have a friend, it has to be CPC. They do a budget multimeter with a temp probe for about 30 (Maxim?)
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geoff

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digital
Maxie, in a previous thread, I Googled, you said the cheapish CPC millimeters and temp sensors were kaka. Now you say buy them. Care to comment? Others read all this too.
Maplin dpo one for circa 19 with temp therocouple. I need a metal probe. Also BES do a similar priced one too. http://www.bes.ltd.uk I think the temp probe is extra.
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If you are looking for one to check surface temperatures accurately (e.g. radiators) then a handheld band probe thermocouple will give good results.
e.g. RS Components 342-8956
There is a metal cup around the thermocouple, which is a spring loaded band. This ensures good contact and shielding from external effects.
I use one of these together with a Fluke 80TK adaptor for one of their multimeters RS 615-488
I am sure that better prices than the RS ones are available - I bought mine in the U.S. checking online sites should reveal lower prices than RS here.
It really depends on how accurate and specific you want to be at the measuring point.

.andy
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All the cheap ones (and some not so cheap) I've seen come with a thermocouple which is part of a semi rigid wire. But I'd say buying a metal probe as an extra shouldn't be too much of a problem given that many use the same type of thermocouple.
However, since you say you're a pro, why not by a pro temperature measuring device complete with calibration certificate?
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writes

I only said that they do a budget multimeter, I was leaving it up to you to assess it's suitability for your requirement
You gave no indication of accuracy, sensitivity and other parameters which would help determine what your requirement is.
I have two of the CPC ones and they have both drifted well out of cal over time

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with
I did say "good and cheap", not cheap and nasty. They are not like throw away power tools. They have to read correctly - throw away power tools drill correctly until they die.

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Actually there are exceptions. I'm sure the Titanic was a quality ship, but it didn't manage to complete its maiden voyage due to a slight disagreement with a bit of ice.
Before now I have paid a premium price for a piece of equipment only to be disappointed at what I paid for. Conversely, I've bought something at the cheap and cheerful end of the spectrum and been very pleased.
Price isn't an absolute measure of quality.
PoP
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A poor workman blames his tools...
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The Titanic was built by professionals.
Noah's Ark was built by d-i-yers
mike r
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There is quite a good booklet called "getting the most from your multimeter" by R.A. Penfold 3 odd. I think it came from Tandy when they did 'good' stuff. It is Babani press no BP239.
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Maplin WP94 - 3.99.
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Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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> >As for hFE this varys from transistor to transistor (even the same

Generally true. A quick 'diode test' on the two junctions and a wet finger to the base gain test is usually enough in the domestic environment.
Either way, these 5 are good value and perfectly good for most DIY use.
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Brian
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for translations try systran a google search should find it.
-- Yours Jason
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This site make give an introduction :
http://www.kaitousa.com/usingamultimeter.htm
Andrew
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On Sat, 6 Dec 2003 12:32:55 +0000, Andy Mabbett

Spot the deliberate mistake.

Here goes.
It is a class of instrument called a V.O.M. (Volt-Ohm-Milliammeter), see the small writing adjacent to the red test plug/socket.
It has two wires terminated in test probes. With the test leads plugged into the sockets as per the photograph..
It can measure DC voltages or intermittent DC voltages presented across the test probes, from 200 millivolts to 600 volts in 5 ranges.
1) V (dc) Legend ----------
2) Intermittent V (dc), Legend - - - - - (Result is the average)
It can measure AC voltages
3) V (ac) Legend ^v^v (Result is approximate) 2 ranges 200 VAC and 600 VAC
It can also measure the DC current or intermittent DC current flowing through the test leads and hence through the meter, you must break into the circuit under measurement to do this. It can be dangerous, even with modest currents (a few mA) flowing high voltages can and will appear across a break in the circuit, and the point at which you are measuring the current might anyway be at an elevated potential, don't for instance measure the anode current of a power output valve by breaking into the anode circuit and have the whole bag of mashings up at 275 volts, measure the volts across the cathode resistor instead, after checking it! Anyway.. 4 ranges from 200 microamps to 200 milliamps.
4) A (dc) Legend ----------
5) Intermittent A (dc) Legend - - - - - - (Result is the average)
6) A single additional 10 amp DC range with a switch position of it's own, use of this range requires that the red positive lead is transferred to the other socket indicated by the 10A switch position, as well as the 10A range selected on the switch.
NB leaving the lead in this low impedance socket will very likely cause damage if the instrument is subsequently used to measure volts. especially *The Mains* ! Most likely the 10 Amps is not routed through the switch and a low resistance shunt is present across this 10 Amp input at all times. This socket is only *Ever* used to make measurements on the 10 A (dc) scale.
7) It can also measure resistances presented to it across the two test leads on 5 ranges from 200 to 2,000,000 OHMS the Legend for the Ohms ranges is the greek letter Omega. (The Ohm [the unit of resistance] was called after George Simon Ohm who discovered Ohm's law. Note that measuring components mounted on printed boards with other components present is very likely to yield results that need careful interpretation. Note also that despite appearances to the contrary the Ohms range actually works by measuring voltages, so if the circuit in question is powered up it is highly likely your measurements will be up the shoot and/or the operation of your circuit may be altered, (Permanently even!). Sort of Schrodinger's Cat/Heisenberg's Uncertainty Principle at work here.
8) It appears it can test transistors inserted into the appropriate transistor socket, there is a range for measuring "hFE", one of the "h" parameters which indicates the (F)orward current transfer ratio in common (E)mitter mode. AKA "Current Gain" a vulgar term.
9) It appears to be able to test diodes which are presumably cunningly inserted in the transistor socket, a bit too small to see, poss. the NPN socket which seems to have some additional inscription on it. This is where the book comes in handy. You can also adequately test diodes by measuring the ratio of their Forward/Backward resistance on the Ohms range, high is good.

HTH
DG
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A small gotha
the polarity of the supply is usaly opostite to the lead colours on a VOM such as yours, but correct on a DVM when reading OHMS
I would also at the first opertuinity replace the glass fuse with a ceramic fuse of same size and fast rateing these can be obtained from RS or farnell.
I would suggest NEVER takeing that meter near mains, the problem is that the mains can send several thousands of amps through it and the arc when you make contact can liberate molteln metal etc. Even a 12V battery under certain circumstances can cause more current to flow than can be dealtwith by a glass fuse.
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What a stupid thing to say.
A voltmeter is designed, and should be able, to test voltages up to the rated maximum voltage (look on the back, it's normally 1000 volts) - set to the correct voltage range of course.
The input impedance of a voltmeter wouldn't let thousands of amps flow. Go home and put a paper bag over your head, there's an ICBM coming
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geoff

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