I want to measure the current draw of a strip of LEDs. This depends on the intensity of the pattern the strips are running so I need to do it in "real time" to get an accurate idea, rather than just do maths from the spec sheet.
I made this cable that should not be in order to insert my multimeter in series with the circuit:
After I plug this in between the (earthed, double-insulated) 12V power supply and LED controller box and clamp the two red wire ends together, everything works fine.
But when I set my multimeter like this:
... and complete the circuit with the multimeter's probes (the red probe on the wire closest to the power supply, black probe closest to the LED's controller box), I get a reading around 3.5A on the multimeter but the controller does not seem to be receiving power and the LEDs don't light.
Any idea what I could be doing wrong?