3 Digit Mini Blue LED DC 100mA Meter. Ideal for CO2 Laser Power Indicator (100mA)

Price: $13.50
48 units available
- +


New version, faster response to current change!


This meter is specially designed for a 100mA measurement (100mA full scale). It's ready to use with a CO2 laser power supply for a current indicator. Just connect it in series with the negative from the power supply to the tube and that will show real time current.


Power: 5V DC +/- 0.2V

Accuracy: +/- 0.5%
Type: LED (blue)
Range: 0-99.9mA
Resolution: 0.1mA
Dimensions: 45mm x 26.5mm x 20mm
Mount hole: 42mm x 25.5mm

Warranty: 3 Months

No shunt is needed and it is ready to use.


Please note: The meter is powered by 5V DC and you need a DC-DC isolated power module if you're trying to power it up using the same DC source with other devices.


Do NOT rely on the color of the wire for connection because it may change. Always looks for marking on the wire hardness: +5V, -5V, -IN, +IN


+5V, -5V (5V power source to power up the meter)
-IN, +IN : +IN  connects to negative of the laser tube, -IN connects to the negative side of the power supply.

Average rating 8 out of 10 ( based on 6 reviews )

Looks good but is a little slow

Review by David on 2/5/2013

This little meter looks great in my K40 laser engraver conversion. You need to keep in mind that a digital meter will have a sampling rate which will cause some lag. This means that when you are doing things like engraving where the laser powers on and off quickly, you will not get accurate readings. However, you will get very accurate measurements when doing long steady powered cuts which makes it ideal for mapping software/hardware settings to actual power output.

Not to be connect in series, but in parallel...

Review by Valentino on 6/19/2013

Good meter, but the description is wrong.

Perfect for Laser

Review by Warren on 11/25/2013

Works great with my 40W laser. Nice bright display and good refresh. Note, prior reviewer is not correct in the hookup.. it is connected in serial with the ground wire from tube to laser power supply unit. BLUE wire from display goes to laser ground on the power supply, and GREEN wire from display goes to the laser tube. There is no shunt resistor required. Just give a +5V from another power supply (logic board, etc.), and connect blue/green in serial and it works perfectly.

No problem install

Review by Vernon on 8/14/2015

I ordered this along with the DSP controller and 24v power supply. Installation was easy. Order the 2405S DC-DC (2 Watt) Isolated power module to get the 5 volts it requires. Wiring diagram for meter and power module included with the DSP controller but I've seen a copy in the discussion forum. Pretty responsive and much better than watching a needle bounce back and forth.

Good dispay

Review by Collector CNC on 2/12/2018

Display update is a little slow but it works well on 5v and it doesn't require a shunt which makes wiring very easy.

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