oh. i see. so what is your means is take the diode and resistor firstly out so the diode and resistor don't to be measured mix with the coil resistance? wait a minute. i trying to desoldering it.

You don't have to physically remove the diode and resistor (though you can if you want to). It is sufficient to simply connect to the circuit in such a way that your are measuring only across the meter movement itself.

 

the result is 100 on AVOmeter test set to x10 ohmmeter.

so the resistance coil about 1k?
for note, when i tested it. the meter make a full deflection so close to the panel meter box.

1kΩ sounds pretty reasonable.

One thing that I should have considered before having you do this is that you are using an analog VOM (volt-ohm-milliamp meter) and so you are probably applying the meter's battery voltage, through a scaling resistor, to the resistance you are measuring. If you have 1.5V across a 1kΩ resistor, then you would expect 1.5mA to flow which we would expect would take your meter movement to close to full deflection.

So let's tread a little more carefully.

Do you have a few resistors handy that are in the roughly 1kΩ to 10kΩ range?

Do you have some 1.5V or 9V batteries handy?

Do you happen to have two VOM meters, or just one?

 

1kΩ sounds pretty reasonable.

One thing that I should have considered before having you do this is that you are using an analog VOM (volt-ohm-milliamp meter) and so you are probably applying the meter's battery voltage, through a scaling resistor, to the resistance you are measuring. If you have 1.5V across a 1kΩ resistor, then you would expect 1.5mA to flow which we would expect would take your meter movement to close to full deflection.

So let's tread a little more carefully.

Do you have a few resistors handy that are in the roughly 1kΩ to 10kΩ range?

Do you have some 1.5V or 9V batteries handy?

Do you happen to have two VOM meters, or just one?

thanks replying

yeah. i understand about your opinion. yes maybe a 27k or 47k ohm if i were guess right. i forgot. because i mix my resistor together without make a value range sign. i have a power adapter 5v and 12v. the battery 9v i haved is almost defective i thought. because it can't really give me a full deflection on my homemade ESR meter.

i have 2 VOM meters. and it was analog both.. so what the next?

 

Unless those power adaptors are regulated, let's avoid them if we can. You only have one 9V battery available? What does it read on your VOM when you measure the voltage? If it reads much below, say, 8.5V can you get a fresh one?

Take some of your resistors and put them in parallel until you get a resistance reading of about 10kΩ. Be sure to zero-adjust your milliamp meter before taking resistance measurements. Also, try to always use a scale that results in the needle deflecting at least through half the range.

Now take one of your VOMs and put it one a scale that will measure 2mA well. Put the other VOM on a scale that will measure 2V well. Put the first meter in series with the meter movement and your resistor and put the second meter across the resistor. Now apply your battery across the series combination of meter movement, milliamp meter, and resistor. Note the voltage, the current, and the meter movement deflection. If all went well, you should have seen a voltage of about 3/4 of a volt, a current of about 3/4 of a milliamp, and a deflection of about half scale.

Report your actual results and we'll then decide how to proceed.

 

Unless those power adaptors are regulated, let's avoid them if we can. You only have one 9V battery available? What does it read on your VOM when you measure the voltage? If it reads much below, say, 8.5V can you get a fresh one?

Take some of your resistors and put them in parallel until you get a resistance reading of about 10kΩ. Be sure to zero-adjust your milliamp meter before taking resistance measurements. Also, try to always use a scale that results in the needle deflecting at least through half the range.

Now take one of your VOMs and put it one a scale that will measure 2mA well. Put the other VOM on a scale that will measure 2V well. Put the first meter in series with the meter movement and your resistor and put the second meter across the resistor. Now apply your battery across the series combination of meter movement, milliamp meter, and resistor. Note the voltage, the current, and the meter movement deflection. If all went well, you should have seen a voltage of about 3/4 of a volt, a current of about 3/4 of a milliamp, and a deflection of about half scale.

Report your actual results and we'll then decide how to proceed.

yeah tomorrow i'll buy the new one battery.
hmm..i don't understand clearly.. could u give a picture schematic explain? second meter across the resistor, paralel means yeah? what its means? and what is means scale measure 2v, it means we set the VOM into voltmeter measure? sorry if i make you busy with my bunch of question please don't mind.. just use ballpoint and draw the schematic is not a problem for me so i can understand clearly.. don't be busy with software..

 

I'm really beginning to get concerned that you are in over your head. You are trying to modify a meter designed to measure hundred of volts so that you can measure 30A of current. That's roughly a thousand times as much current as it takes to kill someone. It isn't going to take much of a mistake for you to end up killing yourself for someone else. I would hate for something that I told you to be misunderstood and for that to end up getting someone hurt because it wasn't sufficiently obvious that a misunderstanding had taken place.

Before you start messing around with stuff like this, you need to take a step back and learn the basics about what it means for things to be in series versus parallel and how to use your VOM to measure voltage and current and you need to build up a level of competence and confidence while working with circuits that will not do much damage, particularly to you, if you mess up.

So please start reading through the E-book, whose links are along the top of the page, beginning with VOL. I - DC. Feel free to ask questions that come up as you work your way through it.

If you feel that this is too much effort to put forth -- which may very well be a perfectly reasonable conclusion to make for your particular interests and situation -- then you need to give up the notion of modifying this meter yourself and hire someone that knows what they are doing to do it for you. It is a simple mod, and so it shouldn't cost much. An alternative is to split for the shipping cost associated with getting the meter you need from an online source.

 

I'm really beginning to get concerned that you are in over your head. You are trying to modify a meter designed to measure hundred of volts so that you can measure 30A of current. That's roughly a thousand times as much current as it takes to kill someone. It isn't going to take much of a mistake for you to end up killing yourself for someone else. I would hate for something that I told you to be misunderstood and for that to end up getting someone hurt because it wasn't sufficiently obvious that a misunderstanding had taken place.

Before you start messing around with stuff like this, you need to take a step back and learn the basics about what it means for things to be in series versus parallel and how to use your VOM to measure voltage and current and you need to build up a level of competence and confidence while working with circuits that will not do much damage, particularly to you, if you mess up.

So please start reading through the E-book, whose links are along the top of the page, beginning with VOL. I - DC. Feel free to ask questions that come up as you work your way through it.

If you feel that this is too much effort to put forth -- which may very well be a perfectly reasonable conclusion to make for your particular interests and situation -- then you need to give up the notion of modifying this meter yourself and hire someone that knows what they are doing to do it for you. It is a simple mod, and so it shouldn't cost much. An alternative is to split for the shipping cost associated with getting the meter you need from an online source.

hmm. I think it's just about don't have a good english about science conception so maybe what do you teach me didn't clear enough for me..
i know what is paralel, series on circuit and ammeter use on series with circuit, voltmeter paralel on the circuit. but your opinion doesn't make me upset. I admitted that my basic is not very well.. maybe i haved to learn more.. your opinion is very useful, anyway thanks a lot for your kinda help sir. after i read the basic maybe I want ask you any question and please help me..

 

hmm. I think it's just about don't have a good english about science conception so maybe what do you teach me didn't clear enough for me..
i know what is paralel, series on circuit and ammeter use on series with circuit, voltmeter paralel on the circuit. but your opinion doesn't make me upset. I admitted that my basic is not very well.. maybe i haved to learn more.. your opinion is very useful, anyway thanks a lot for your kinda help sir. after i read the basic maybe I want ask you any question and please help me..

Sounds good. It may well be that the problem is purely a language barrier issue instead of a concept problem, but of course it doesn't really matter what the underlying reason is for the miscommunication that kills you.

I will be happy to help you with the basic stuff and we can work our way back into this task pretty quickly, I imagine.

 

Sounds good. It may well be that the problem is purely a language barrier issue instead of a concept problem, but of course it doesn't really matter what the underlying reason is for the miscommunication that kills you.

I will be happy to help you with the basic stuff and we can work our way back into this task pretty quickly, I imagine.

anyway.. thank you very much sir