Analog voltage tester?

[Knobhead]

well we still need entries in the trainee area lol

Marvo won't let me in.

 

[Besoeker]

I use an old Kyoritsu analogue multimeter. It's always been reliable and accurate and I picked it up for next to nothing at a stall on a market. Maybe keep an eye on Gumtree or similar classified advertisements sites, analogue testers aren't fashionable because they don't sync with facebook and instagram so youngsters nowadays won't touch them with a bargepole. If you bide your time and keep your eyes peeled you'll get one for a song.

Here in UK, car boot sales are sometimes a good source for all sorts of bargains including electrical gear.

Somewhat off topic but we picked up a new DVD player, still in the original box and complete with manual for just a fiver. A whole box of cable ties for 50p. A digital multimeter for a quid.

 

[HappyHippyDad]

Would any analog voltage tester be suitable for testing to see if real or phantom voltage? Everyone seems to be mentioning the older types (i.e Avo8 etc), would a new analog multimeter still do the job?

For example:

GENERAL PURPOSE ANALOGUE AC DC MULTIMETER VOLTMETER NEW | eBay

 

[7029 dave]

Beware that many cheap multimeters, analogue and digital, won't comply with GS38 and will be unsafe for testing electrical installations due to the level of potential fault currents and voltage spikes. If all you want to do is prove whether a 230V supply is real or phantom, a test lamp will do just fine:

Drummond Test Lamp Mtl7 150-500 Ac/dc New Without Packaging | eBay

MTL7 DRUMMOND Test Lamp New and sealed. | eBay

With fused test leads they will comply.

 

[Richard Burns]

Would any analog voltage tester be suitable for testing to see if real or phantom voltage? Everyone seems to be mentioning the older types (i.e Avo8 etc), would a new analog multimeter still do the job?

For example:

GENERAL PURPOSE ANALOGUE AC DC MULTIMETER VOLTMETER NEW | eBay

It really depends on how they have managed the electronics inside the meter.
The old style analog meters had a high resistance in series and this gives a voltage reading across the resistance but there is some flow of current acros this resistance that will (very slightly) drop the votlage and give a lower reading.
However modern meters use electronics to create a practically infinite resistance against which to measure the voltage, this gives accurate values of voltage without any loss through the resistance, however this is very definitely the unloaded voltage and this means the presence of a large potential difference with no capability of supplying current will register as a voltage even though for all practical purposes there is no voltage present.

If the meter manufacturer uses a modern infinite resistance system and uses electronics to transfer this to a needle on a meter dial then it would be the same as any modern unit.
I do not know the availability of standard chips that would make this construction straightforward but I would expect the cost would be greater than a standard analogue arrangement so the ease of making a basic deflection meter means that they probably would not bother and that a modern analogue meter would be fine.
However others may know different.

 

[Simonslimline]

You cant go wrong with a simple Drummond test lamp. I picked up a brand new one off Ebay for £25.

 

[HandySparks]

The point is this. What you need to confirm that a voltage is 'real', not phantom, is a meter or indicator that loads the supply sufficiently. The figure that matters is its input impedance; a low input impedance will load the circuit under test and pull down a phantom voltage to a level close to zero. A 'real' fault will be unaffected and the full supply voltage will be indicated.

Clearly, a test lamp will load the supply as it has (relatively) a much lower resistance than the inductive or capacitive 'fault' and will try to draw much more current than a phantom voltage will supply. 'Simple' analogue meters will also load the supply to a greater or lesser extent.

Digital meters and the 'better' analogue ones will have a high impedance, which is exactly what you need for most electronics work, so that the meter doesn't significantly affect the voltage you're trying to measure.

The Fluke TL225 / SV225 mentioned by Marvo puts a 3kohm resistor across the circuit being measured so that a high impedance meter behaves like a low impedance one.



(I've covered some of the same ground as Richard Burns but I thought it worth saying anyway.)

 

[stevethesparks]

This is one reason I recommend the Fluke 117 as an electricians meter (although not analogue) as it has a lowZ setting of which eliminates ghost voltages.

 

[shanky887614]

It really depends on how they have managed the electronics inside the meter.
The old style analog meters had a high resistance in series and this gives a voltage reading across the resistance but there is some flow of current acros this resistance that will (very slightly) drop the votlage and give a lower reading.
However modern meters use electronics to create a practically infinite resistance against which to measure the voltage, this gives accurate values of voltage without any loss through the resistance, however this is very definitely the unloaded voltage and this means the presence of a large potential difference with no capability of supplying current will register as a voltage even though for all practical purposes there is no voltage present.

If the meter manufacturer uses a modern infinite resistance system and uses electronics to transfer this to a needle on a meter dial then it would be the same as any modern unit.
I do not know the availability of standard chips that would make this construction straightforward but I would expect the cost would be greater than a standard analogue arrangement so the ease of making a basic deflection meter means that they probably would not bother and that a modern analogue meter would be fine.
However others may know different.

thanks rich for the very informative post

 

[shanky887614]

This is one reason I recommend the Fluke 117 as an electricians meter (although not analogue) as it has a lowZ setting of which eliminates ghost voltages.

could always put a resistor across the leads

 

[telectrix]

you'd put the resistor in parallel with the leads. that would then drain phantom voltage that the dmm won't.

 

[HappyHippyDad]

Thanks all for the advice.

I have decided to go for the Drummond mtl20! Thanks Handy Sparks :smile5:

 

[happysteve]

you'd put the resistor in parallel with the leads. that would then drain phantom voltage that the dmm won't.

Spot on

You'll have a job doing this and still having a "safe" instrument/set of leads. Could probably do it with a plug-in box - but it's a lot of work when you could buy a Drummond

 

[davesparks]

Any approved voltage indicator (AVI) should differentiate between a ghost and a real voltage.

 

[happysteve]

Any approved voltage indicator (AVI) should differentiate between a ghost and a real voltage.

I'd love to believe this. The input impedance of my Martindale isn't quoted, but the manual says, "Test current: <3.5mA at 600V" which implies an input impedance of at least 170k. Not the 1M (or even 10M) of a DMM, but pretty close. The Drummond also pulls "<3.5mA" unless you press the button, in which case it will draw "28mA @ 240V AC, 60mA @ 500V AC."... Zin ~ 8k. Fluke's Lo-Z function is "about 3k" (according to Fluke literature).

Also, I have a Dilog voltage indicator, it bleeps and warbles and lights up like a Christmas tree when touching anything conductive vaguely close to something that might be energised. (Which is why I bought the Martindale).

So, although not doubting what you say, I am left a little confused!

 

[davesparks]

I'd love to believe this. The input impedance of my Martindale isn't quoted, but the manual says, "Test current: <3.5mA at 600V" which implies an input impedance of at least 170k. Not the 1M (or even 10M) of a DMM, but pretty close. The Drummond also pulls "<3.5mA" unless you press the button, in which case it will draw "28mA @ 240V AC, 60mA @ 500V AC."... Zin ~ 8k. Fluke's Lo-Z function is "about 3k" (according to Fluke literature).

Also, I have a Dilog voltage indicator, it bleeps and warbles and lights up like a Christmas tree when touching anything conductive vaguely close to something that might be energised. (Which is why I bought the Martindale).

So, although not doubting what you say, I am left a little confused!

Which dilog AVI are you using? I have always used the combivolt ones and they show a clear different result when detecting real and ghost voltages.

I agree the noises can be the same but if it is real then the red LEDs illuminate up to the nominal voltage present, wheras ghosts only light the single red LED.

As with any test equipment you have to learn to use it correctly and how to interpret the readings.

 

[happysteve]

Which dilog AVI are you using? I have always used the combivolt ones

Yep, that's the chicken. (Well, combivolt twos...)

As with any test equipment you have to learn to use it correctly and how to interpret the readings.

Well that's me told. Guess I've got some more learning to do.

Cheers.