OK, now that Kiriakos is gone, I think we can safely talk about cheap(er) meters.
Basically, I've been experimenting with a few digital ammeters on the load tester. The last one I've tried was one of these - http://www.amazon.com/Watts-Meter-An.../dp/B001B6N2WK. It works great at 12V. With a 5ohm (2.4A) load, it reads 2.38A - probably nothing that can't be explained by small losses in the wires and some tolerance in the resistors.
on the 3.3V rail, though, it's not as accurate - with a 0.33ohm (9.7A once you factor in the vreg) Load, it reads 8.3A - off by 1.4A (and yes, it is being powered by an external 12V supply).
So, here's the question - what would be a decent panel mount ammeter to use that offers reasonable accuracy at low voltages and can measure up to the 35A my load tester is capable of pulling on the 3.3V rail?
I was thinking about using these - http://au.element14.com/murata-power...ter/dp/1339334, as they are intended to work with a separate power supply to the one which is powering the measured load. However, 8V is listed as the minimum supply voltage. Would they work accurately when measuring lower voltages if they were powered by a higher voltage (like 12V)?
Basically, I've been experimenting with a few digital ammeters on the load tester. The last one I've tried was one of these - http://www.amazon.com/Watts-Meter-An.../dp/B001B6N2WK. It works great at 12V. With a 5ohm (2.4A) load, it reads 2.38A - probably nothing that can't be explained by small losses in the wires and some tolerance in the resistors.
on the 3.3V rail, though, it's not as accurate - with a 0.33ohm (9.7A once you factor in the vreg) Load, it reads 8.3A - off by 1.4A (and yes, it is being powered by an external 12V supply).
So, here's the question - what would be a decent panel mount ammeter to use that offers reasonable accuracy at low voltages and can measure up to the 35A my load tester is capable of pulling on the 3.3V rail?
I was thinking about using these - http://au.element14.com/murata-power...ter/dp/1339334, as they are intended to work with a separate power supply to the one which is powering the measured load. However, 8V is listed as the minimum supply voltage. Would they work accurately when measuring lower voltages if they were powered by a higher voltage (like 12V)?
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