MEASURING DC VOLTAGE AND CURRENT USING THIS METER ?

[magnetman12003]

What is the correct way to measure voltage and current together using this particular meter.

I plan to use 24 DC volts input to power the meter. 

My load will be a 50 watt DC 220 volt LED bulb and I wish to accurately measure both voltage and whatever current the bulb is using.

Here is the meter I intend to purchase .  Can someone tell me exactly how to hook it up to accomplish the above.  I see 4 ways to do that on this Ebay site.  Do I need the extra shunt?

http://www.ebay.com/itm/DC-0-600V-500A-Voltmeter-Ammeter-LCD-Panel-Amp-Digital-Volt-Gauge-meter-12V-24V-/271808226581?pt=LH_DefaultDomain_0&hash=item3f49086515

[Void]

What is the correct way to measure voltage and current together using this particular meter.
I plan to use 24 DC volts input to power the meter. 
My load will be a 50 watt DC 220 volt LED bulb and I wish to accurately measure both voltage and whatever current the bulb is using.
Here is the meter I intend to purchase .  Can someone tell me exactly how to hook it up to accomplish the above.  I see 4 ways to do that on this Ebay site.  Do I need the extra shunt?
http://www.ebay.com/itm/DC-0-600V-500A-Voltmeter-Ammeter-LCD-Panel-Amp-Digital-Volt-Gauge-meter-12V-24V-/271808226581?pt=LH_DefaultDomain_0&hash=item3f49086515

Hi magnetman12003. I haven't used that meter before, but I read through the description
on that ebay webpage, and from what I understand you should be good with the first wiring diagram.

From what I understood, if you power the meter with an external separate power supply between 3VDC to 40VDC, then
you can measure DC voltages from 0V to 600VDC with the meter. So with your separate 24VDC power supply connected
to pins 3 and 4 as shown in the first wiring diagram, you should be able to measure DC voltages from 0V to 600 VDC.
Pin 3 is negative, Pin 4 is positive.

The meter apparently comes with an internal shunt that is good for measuring DC currents up to 10 Amps, again, 
from what I can understand.   So with your 50 Watt, 220V LED bulb, it should only be drawing around 0.227 Amps, so it
should be well under 10 Amps. That being the case you don't need to order an extra shunt for the meter for currents
under 10 Amps. You could order one of the higher current shunts if you think that at some point you may want to
measure high DC currents with the meter for some other project.

So, it looks like for your criteria above, that the first wiring diagram is what you want, and you don't
need an extra shunt.

From the diagram, to measure the DC current you place the meter (through pins 1 and 2) in series with your light bulb,
on the negative side of the light bulb as shown in the first wiring diagram. Just follow the first wiring diagram for all the pin connections.

All the best...

[magnetman12003]

Hi magnetman12003. I haven't used that meter before, but I read through the description
on that ebay webpage, and from what I understand you should be good with the first wiring diagram.

From what I understood, if you power the meter with an external separate power supply between 3VDC to 40VDC, then
you can measure DC voltages from 0V to 600VDC with the meter. So with your separate 24VDC power supply connected
to pins 3 and 4 as shown in the first wiring diagram, you should be able to measure DC voltages from 0V to 600 VDC.
Pin 3 is negative, Pin 4 is positive.

The meter apparently comes with an internal shunt that is good for measuring DC currents up to 10 Amps, again, 
from what I can understand.   So with your 50 Watt, 220V LED bulb, it should only be drawing around 0.227 Amps, so it
should be well under 10 Amps. That being the case you don't need to order an extra shunt for the meter for currents
under 10 Amps. You could order one of the higher current shunts if you think that at some point you may want to
measure high DC currents with the meter for some other project.

So, it looks like for your criteria above, that the first wiring diagram is what you want, and you don't
need an extra shunt.

From the diagram, to measure the DC current you place the meter (through pins 1 and 2) in series with your light bulb,
on the negative side of the light bulb as shown in the first wiring diagram. Just follow the first wiring diagram for all the pin connections.

All the best...

Thanks for your help on this.  I see I can use the meter now to compare input and output of
the device I am working on.

[magnetman12003]

Hi magnetman12003. I haven't used that meter before, but I read through the description
on that ebay webpage, and from what I understand you should be good with the first wiring diagram.

From what I understood, if you power the meter with an external separate power supply between 3VDC to 40VDC, then
you can measure DC voltages from 0V to 600VDC with the meter. So with your separate 24VDC power supply connected
to pins 3 and 4 as shown in the first wiring diagram, you should be able to measure DC voltages from 0V to 600 VDC.
Pin 3 is negative, Pin 4 is positive.

The meter apparently comes with an internal shunt that is good for measuring DC currents up to 10 Amps, again, 
from what I can understand.   So with your 50 Watt, 220V LED bulb, it should only be drawing around 0.227 Amps, so it
should be well under 10 Amps. That being the case you don't need to order an extra shunt for the meter for currents
under 10 Amps. You could order one of the higher current shunts if you think that at some point you may want to
measure high DC currents with the meter for some other project.

So, it looks like for your criteria above, that the first wiring diagram is what you want, and you don't
need an extra shunt.

From the diagram, to measure the DC current you place the meter (through pins 1 and 2) in series with your light bulb,
on the negative side of the light bulb as shown in the first wiring diagram. Just follow the first wiring diagram for all the pin connections.

All the best...   The first diagram shows the load on the positive side?  Do I switch the load (bulb) to the negative side?

[gyulasun]

magnetman 12003 wrote:

The first diagram shows the load on the positive side?  Do I switch the load (bulb) to the negative side?

Hi,

The first diagram shows the load in parallel with the DC voltage source to be measured. Though it looks like the load is on the positive side by the schematic drawing style but if you consider the ampermeter pins 1 and 2 as a piece of wire (due to the very low value built-in shunt resistor) then you understand the load is simply connected across the DC voltage source to be measured.

The correct question to ask is: which side of the load is the ammeter inserted, okay? This is because for a load when connected across a DC voltage source, you cannot distinguish which side it is on, it is on both the positive and the negative sides, ok? (once it is connected in parallel with the voltage source)
It is okay that your load will be a LED lamp which would have a positive and a negative connections to consider (you wrote it is a 220V DC LED).
So the answer to the correct question is: the ammeter is inserted at the negative side of the load and this is shown in Graph 1 what member Void kindly attached for you.

A suggestion: you could use a normal 9V alkali battery to feed the meter once it is able to operate from as low as 3V DC, to simplify things.  But of course the power supply is also correct to use.

Gyula