Ammeter

[SJTD]

Anyone splain to me how this would work? https://www.amazon.com/gp/product/B08X4 ... 2O7P&psc=1

It appears that the probe is an inductive device rather than a shunt and so would only work with AC. Or am I remembering what little I learned about electrickery incorrectly being an ME?

[tgreese]

I'd guess - you can't sense the constant current by induction, but you can sense the differential current. This meter has to be an integrator, which adds up the changes in current. It's a stepper in the sense that the sense coil signal steps it up or down. There has to be more to it, since an op amp (passive) integrator depends on charging a capacitor, and a capacitor will eventually leak down. Considering how cheap CPUs are today, possible there is a digital algorithm in the meter that resets to zero when the key is off, and maybe other processing that integrates digitally, or something else fancy. coil -> op amp -> ADC -> CPU? Suspect it also connects to DC voltage which could be another input.

Might be a spinoff from solar panel charge tracking? I'd expect panels connected to batteries would invert to AC after charging the batteries as DC. One would want to measure the DC current output.

[SJTD]

Yeah, I was hung up on induction.

Seems the DC probe works by measuring the hall voltage, whatever the heck that is, produced by the constant magnetic field from the DC current. Saw a neat Youtube where he was showing that for really low currents the probe had to be zeroed to cancel out the earth's magnetic field whenever it was reoriented.

[will e]

I have a multimeter that inductively detects DC amps. Klein Tools CL800. I just used it on the Jeep to test draw for an on board air compressor and it was accurate.

[will e]

Autometer makes one that also uses and Current Transducer.

https://www.autometer.com/pub/media/man ... 0-999X.pdf