# Need help wiring a mini digital Amp Meter

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Hello please help, I have 2 analog 30 amp meters with shunts I have wired up and working fine but these new digital 10 amp meters are confusing and the seller stated I do not need a shunt.

Im confused if it needs a separate power supply for the led as I tried one of them with same power supply and one with separate power supply for led it lights up but amp readings drop rapidly and or are different.

It does state no extra supply for 4.5-30 V but like I said led would not light up but maybe I did something wrong ?

I dont want to short anything out so advise would be much appreciated. I have contacted seller but who knows what kind of reply it will be...

Here is the link to the meters I have https://www.ebay.com/itm/173647061094

another meter of similar design show 2 ways to wire up, one with same power supply as load and one with separate dedicated power supply for led.

Specs here .
1. High-precision measurement of DC 0-10A current, no extra supply for 4.5-30V .... ?
2. Simple wiring, with anti-collision shell design, dust-free workshop production, imported original chip.
3. Low-start operating voltage, reverse-connection protection, reverse-non-burning, and fine-tuning function.

Specifications:
Input voltage: 4.5-30V
Measuring range: DC 0-10A
Current measurement error: 1%
Working current: < 30 mA
Display mode: 0.56" LED digital display
Refresh rate: about 200 ms / time
Line length: 19.5 cm/7.68"
Working temperature: -10 ° c~ -65 ° c
Working humidity: 10%-80%
Digital display color: red, yellow, green, blue
Product size: 47*28*17mm/1.85*1.10*0.67"
Net weight: 16g
Gross weight: 24g

#### panic mode

Joined Oct 10, 2011
1,788
1. why did you buy something without datasheet or at least the most rudimentary instructions?
2. why don't you contact seller?
3. if you already have it, why don't you take a CLOSEUP picture of the circuit so we can offer meaningful response?

Joined Mar 10, 2018
3,578
Sure sounds like it has internal shunt. Also one set of wires for power,
one for inserting in series with current to be measured.

Any marking on plastic shell, or inside on board ?

These China displays so cheap hard to ignore but often docs little or none.

Take a pic of board with case off and post, might give us some clues.

I suspect red and black for led/circuit power, and blue / brown for current
detection. When you open up case look at where blue and black come intro
board, should see a shunt across them, a SMT resistor or a long copper trace
between the two leads acting as a shunt.

Regards, Dana.

#### whitehaired novice

Joined Jul 15, 2017
283
There are a lot of sellers of such meters. Some of them post diagrams of how to set your meter up either of two ways, self powered or independently powered. Look at other sellers for similar meters til you find one who does post such diagrams--I have seen them.

#### whitehaired novice

Joined Jul 15, 2017
283
Go here in ebay 0.56in Mini Digital LED Display Ammeter Panel Amp Measuring Current Meter Tester

mouse WAY, WAY down, past far more pictures than you would care to.

Diagrams of how to hook it up with and without using external power source.

Joined Mar 10, 2018
3,578
Yes, the shunt is internal. To confirm it should show connections to
blue and brown wire, or use an ohmmeter across blue and brown,
should show single digit ohms, possibly < 1 ohm. Remember to
subtract out ohmmeter test lead resistance.

Regards, Dana.

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Go here in ebay 0.56in Mini Digital LED Display Ammeter Panel Amp Measuring Current Meter Tester

mouse WAY, WAY down, past far more pictures than you would care to.

Diagrams of how to hook it up with and without using external power source.
THanks I did see that one also, I will post up if I get a reply from seller.

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
Yes, the shunt is internal. To confirm it should show connections to
blue and brown wire, or use an ohmmeter across blue and brown,
should show single digit ohms, possibly < 1 ohm. Remember to
subtract out ohmmeter test lead resistance.

Regards, Dana.
Thank you for the helpful reply !

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
I measured separate slot inside pin to inside pin with my multi meter in lowest 200 setting it reads 0.8 and also separate slot outside pin to outside pin are the same ohms reading, only those to configurations get a reading...

Not sure yet how that helps, could it mean I can wire it 2 ways one with dedicated power supply and one with shared power supply ?

The selling is not in the office today so the wait timer is counting down...

#### HonesTisThePathToLife

Joined Nov 25, 2018
27
This arrived today but it does not even get a reading this way, the led lights up but no load readings as the load is not getting power....

When I do a separate battery source it gets readings and powers the load but they readings very... Maybe they are selling someones garbage ?

I will try 1 more time separate power source setup and see what happens, but sounds like garbage so far..

If it looks strange do caution me please...

https://www.dropbox.com/s/usi5i4osewlzf92/20181217_174839.jpg?dl=0

Ok

Last edited:
Im sure those ebay meters are garbage not sure why they are doing that but I will be asking for refund...