Measuring laser power with an analog mA meter


It’s cheap and it’s a must

When you cut using a laser cutter, you need to know how much power your power supply is delivering to your laser tube. Fortunately, this is very cheap to implement.b5b530d8-6976-4773-96f9-01ebd4c7c716_1-45a8a82459b83d2e8ba673cda44feb27

For $4-$5 you can find cheap analog panel meters on Ebay. These meters can be found in a lot of ranges from a couple of µA over mA to full amps. For a laser cutter you can do with a DC panel meter in the 0-30mA range. 30mA is already overkill unless you use high quality 100+ Watt tubes. More common tubes like 40-50Watt use far less than 30mA.


Your power supply is connected to your laser tube with 2 wires. The large (mostly red) wire is a high voltage wire which you SHOULD NEVER TOUCH. It should be directly connected between power supply and tube and nothing else. Never try to alter it if you like to live 🙂


Instead, you can simply connect the mA panel meter by cutting the return wire and connecting the meter there. This return wire is not as dangerous as the red wire so you are safe to do this.

Of course, always take precautions. Power off your machine. Disconnect from the wall socket and let the machine rest for at least 1 full hour to give capacitors time to discharge.

Good luck! Now you can measure accurately how much current is going through the tube.

And be aware, but a DC meter, not AC!

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