ABB Interview Question

Two pieces of wire will suffice (even fewer if the "metres" have probe leads). The "voltmetre" will read 220 if connected to the 220v supply; the "ammetre" may just blow up (depending on what kind of "ammetre" it is). Wear safety gear.

so an general answer can be the metre which shows more deflection will be ammetre and the one which shows less deflection will be the voltmetre.will that be correct

Maybe, and maybe not. For one thing, it would depend on the scales of the respective "metres."

The one that survives is the voltmeter; that description is correct.

<< The one that survives is the voltmeter; that description is correct >>

Please modify to read:

The one that deflects is the voltmeter; that description is correct

No. The ammeter is not destroyed but needs much heavy current to deflect; while Voltmeter has Hi-Resistance and just draws mA(s) to FSD which cannot damage ammeter.

It is a normal tip from techies who test any appliance by connecting a bulb in series which protects the device or Electric supply.

I'd go and get a 100k resistor...
Del

would you get a series resistor or a parallel resistor?

thanks john.for ur post culd u give a brief reasoning for ur answer

A voltmeter has a very high impedance (it would be infinite for an ideal one), so will pass very little current. An ammeter, on the other hand, has a low impedance (it would be zero for an ideal one), so drops very little voltage (particularly if the current is tiny).

So with the two in series, the ammeter would behave like a piece of wire - essentially no voltage drop, so the voltmeter would see the full 220 volts. Also, because of the very high impedance of the voltmeter, very little current would flow through the ammeter (so it would read very nearly zero).

Is this really from an ABB interview? What kind of interview?

Do you really know what the two meters are? What their functions are? And how they are used?

Smart thinking John, if this was a real question, I would have to bet your solution is the correct answer.

I was going to say the one with the "V" to the right of the digits (on the display) is the voltmeter.......... Of course, this only works if it's digital.

Sorry, couldn't resist

Tom D.

thanks john.................for a job interview actually...................grt answer

It would be a lot safer to put them both in parallel to the power supply and in series with each other. That way the meter reading 220 is the voltmeter and the meter reading near nothing is the amp meter and no one ran huge amounts of current thru a wire.

Basics of meters: volts measure in parallel and amps measured in series (in the circuit).

edited: agree with the reply. I just misread it the first time thru

Who voted JohnDG's answer as "Not a GA"??? ....

I had to undo it...FYI...

Does spelliing and grammar count for your interview. If it does, u might want to spell check your work before u hand it in.

It's amazing how quickly 1 loses credibility when u use txt shorthand. Especially when asking a technical question. It's a sad situation when our kids thinks it's OK and proper to use this form of communication when asking for or conveying information. I, myself find this scary to think that these kids are our future Rocket Scientists

Dear Raesh,

YOU HAVE GIVEN EXCELLENT REPLY and it took 3 minutes for me to stop laughing.

It is said LAUGHTER IS THE BEST MEDICINE - I am sure the high blood pressure could have come down.

Thanks,

RAJESWARI.

GA.. my thoughts too! Scary huh?

Regards.

I think it is too early to grade an Institute, a country or a group on basis of a single person.

Almost all Hi-Techs have some counts of all standards.

It the average of population which counts for.

I feel 22 V is OK though but don't add any zeroes, even a single one anywhere except as the leftmost digit.

And then too don't let him play with multimeters and try to take the internal impedance of human body (there is a Darwin nomination on this)

Sorry It must be him or her though without seeming to look sexist, I feel the former is true, since I have found tha later to be a little more sincere, but then in today's age I am not too sure, may be they too have progressed to attain the equality of sexes.

Look at the questions (looks like all from ABB interview) asked by the OP. Now can you really imagine someone asking how a rotating magnetic field generated in DC Poles of Syncghronous generator or motor?

DC machine would have been a bit upto the mark I feel, AC coils of machines a bit below that in merit. But...

Do they teach now a days or the students refuse to get taught?

The next question- Why the Induction motor coils create a rotating field but not the ones in transformers?

let us form a few more should we?

Connect the two in parallel and place them in series with the supply, the Ammeter will show the current flow, the Voltmeter will show zero

... for the couple of milliseconds before the ammeter blows up. Then (if there's anything left of it) the voltmeter will indicate 220V.

I didn't say across the supply!!!!!

I said in series with the supply - IE between the supply and the load!!!

What an idea of "IN SERIES WITH SUPPLY"?

And iwhat is the meaning of ACROSS THE SUPPLY?

Anyhow Ammeter will flash and voltmeter if not just near may be safe to indicate.

Please try to understand that Ammeter cannot be connected as you said, but some load is to be connected in series of it and power supply.

oh... this is code for calculating voltage drop, hence the voltmetre/am[p]metre. but i don't understand how one gets 4 and a half pieces of wire?