How does voltage transducer works?

I want to know how a voltage transducer works..any exact circuit to show that how a voltage like 110V AC become to 4-20mA signal..and how sensing side of transducer works?

The first question is what? Voltage transducer

So what do you do here

Use google, Look up Voltage transducer

Thats the first step
Read it, make some notes, decide what other questions you may have

Write those down

Come back to the forum and discuss what you have read and understood
Followed by other questions you may then have and we will then guide and assist you further

ALSO Good english is as such

Ask politely, example "HI I wonder if someone could assist me please

Im having difficulty understanding what a voltage transducer is

Could someone explain this to me or provide possible links as to where I might gain more information "

ITS VERY RUDE TO ASK LIKE THIS, "I WANT..
."

LOTS OF PEOPLE WANT, BUT NOT EVERYONE GETS WHAT THEY WANT BESIDES WHICH YOU NEED TO ASK NOT DEMAND

Adopt this attitude on first request you will imiediatley allianate yourself and NO ONE WILL HELP YOU

Just so you have a diverse first experience posting on this forum, let me say that I didn't hear any of the "negative tone" that Mark is chastising you for (i.e. your tone doesn't sound demanding to me ;)

I'm not familiar with voltage transducers but judging by the data sheet for the LV25-P, it uses a hall-effect device to sense the magnetic field generated by a current passing through the transducer -- so, it's really a current transducer. Voltage is measured by passing a current proportional to the measured voltage (set by an external resistor). The resistor, in series with the transducer, is applied across the voltage to be measured.

Here's the datasheet:

http://www.europowercomponents.com/media/uploads/LV25-P-SP2.pdf

BTW, I Googled _Voltage Transducer_ (and _How does a Voltage Transducer work_) and found very little information.

Now, regarding the 4-20ma signal and how 110VAC is _converted_ to a 4-20ma loop, are you looking for a circuit that _measures_ (or _monitors_) 110VAC and sends that information via a 4-20ma loop?

There is a wealth of information at the end of a Google search on "4-20ma circuit". Give that a try, and then, as Mark suggested, ask a more specific question in a fresh post (so it gets more exposure than it would if asked here).

There are many devices that are considered transducers.The question cannot be answered as asked! Now if there was a specific tranducer mentioned that portion of the question could be addressed. Then attention could be brought to the second queston asked and that is; Can this device be used with 110v AC?

*DICTIONARY*
transducer
Definition
trans·duc·er[ tranz dssər ]trans·duc·ers Plural

NOUN
1. device that converts energy: a device that transforms one type of energy into another, e.g. a microphone, a photoelectric cell, or an automobile horn
2. biological converter of energy: a biological entity that converts energy in one form to another, e.g. the rods and cones of the eye or the hair cells of the ear
[ Early 20th century. < Latin transducere "lead across, transfer" (see traduce) ]

There are many types of transducers. You don't ask what kind. Having said that there are many things written on Wiki pages that discuss transducers of varying types. Pick one.

Just for reference this is not being negative at all Its commonly known as basic mannors and it isnt "I want at all", neither has he bothered to look anything up

You obviously havent had the pleasure of workng with "I wants, or the obnocious phone calls from so called Directors etc nevemind some of the less distastefull influences in life"

Basic mannors cost nothing in life and retrieve far greater results Its no wonder we have appauling attitudes such as this

So with all due respects Im quite right to point this out

You may tolerate this I dont You may talk to other people like this but with me If you want help then you ask nicely

Take a ferrite rod and wound it with 3 to 4 hundred turns of 36 gauge enamelled copper wire preferably evenly so that loses are reduced. connect coil terminals to transistor DC amplifier. Connect a low impedance device in collector circuit through which you want to flow 4 to 20 mA of current.

Switch on transistor circuit. Take coil core near to AC 110 V line, you may find current as expected by you through your device or in collector circuit.

Ferrite core coil works like magnetic transducer, it picks up the magnetic fluctuations taking place in AC 110 Volt line due to current flow in line.

Coil produces weak fluctuations of AC voltage, which is then amplified by transistor circuit. Collector of the circuit can provide 4 to 20 mA of current through low impedance device connected at collector. low impedance device could be a 100 Ohm resistor.

You will, of course, need to include all the support circuitry to calibrate this and temperature stabilize it. Also, to get a consistent reading, the ferrite rod will need to be secured, somehow to the AC line, or rigged to achieve a repeatable orientation with the AC line. In other words, it's a bit more complicated than Kamble's description.

Unless this is merely to be some sort of "proof of concept" or demonstration.

Hi mark
First I want to apologize for what you consider as "RUDE STUFF" and assure you that I`m not like that kind of man may appeared from my question.
then I tried so much to find some thing exact about a voltage transducer. you know that electronic producers do not give complete information about their gadgets! what I meant from my Q was that could any one help me to find exact circuit of a voltage transducer which senses 110 V AC and convert it to 4-20mA current signal..how it happens? and every thing like that.
thanks so much.

Dear Steve
First let me have my appreciate to your friendly manner then I want to say YES for this part of your post:

"Now, regarding the 4-20ma signal and how 110VAC is converted to a 4-20ma loop, are you looking for a circuit that measures (or monitors) 110VAC and sends that information via a 4-20ma loop?"

what exactly I have is a IME model TM3UL20 voltage transducer. this transducer senses 110 V AC and convert it to 4-20mA current signal. I have some problems with this kind of transducer. after a period of working like 1 or 2 years it sends 21 to 22 mA for 110 volt AC in its sensing line. this is common problem in instruments like a Voltage transducer that you can fix it by adjusting its Zero or Span potentiometer. but problem starts from here that by adjusting zero and span potentiometer in their minimum position current signal dose not reduce and you still have 21 to 22 mA! this makes a big error in what you measure and send back to control center.
now I wonder to find out more about this kind of voltage transducer in particular and common concept of all voltage transducers. like how exactly they sense voltage and then convert it to a 4-20 mA signal..
I also have to say that I don`t want or cant just replace with other brand or thing..

Sounds like what you are saying is that your TM3UL20 has gone out of calibration and won't come back into calibration with adjustment of the span and zero controls.

Like you said, the manufacturer is unlikely to divulge the inner workings of their device. Perhaps you can locate a patent for it. Other than that, I have nothing for you, sorry. Perhaps someone else here does.

If you're adventurous, perhaps see if you can disassemble it and reverse engineer it. Or maybe someone here can recognize a key internal component (or two) and help you figure out how it works.

Also, if you _do_ disassemble it, perhaps you can find a resistor that has overheated and thus increased in value, or some other such easily identifiable failure.

Hello.
I am also in the need of measuring voltage.
I was thinking in doing it with 2 resistors in series and this configuration in pararell with the load I want to measure the voltage from. The resistance of this arrange is much biguer than the one I am measuring from.
The proble I have, is with the ground of the micro that will aquire the voltage, does it have to be conected with ground of the load, is this dangerous for the Micro?.
This Micro is also conected to the Current transducer (that is working fine):

http://www.lem.com/docs/products/hlsr-p_sp33_series.pdf

So i havent try this voltage sensing configuration, for not burning anything yet.

Thanks a lot.

I attach a picture of the configuration.

Looks like you are trying to measure the voltage "V1" using a Voltage Divider composed of the resistors "R1" and the 250Ω resistor. The question of whether it's safe, or not, to connect the Microcontroller's [MCU] ground to the Test Point ground depends on what is powering the MCU. If it's battery powered, then no problem (unless high voltages are involved (50V or more), and there is the possibility for someone to touch it--i.e. electrocution potential). Otherwise, I suggest using something like an opto isolator to do this measurement.

Check this out for possible ideas on how to do this:

http://electronics.stackexchange.com/question...ct-way-to-measure-voltage-with-an-optocoupler

or this:

http://electronics.stackexchange.com/question...measuring-voltage-while-maintaining-isolation