On 31/07/2015 2:32 PM, Ron D. wrote:
Audio load: http://www.mcmelectronics.com/product/28-048 (No mention
of tolerance)

Done.

Scopes have a lot of errors. A DVM may work, but pay attention to
frequency response. If you stick to a sine wave you won't need a
TRMS meter.

**Digital 'scopes often have true RMS display capability, with excellent
accuracy.


Next problem, you need to know the resistor value accurately.

I don't think you want or need want 0.001% accuracy.


**Far and away the biggest source of inaccuracy lies with line Voltage
regulation. Or lack of it. I would certainly not panic about resistor
accuracy nor 'scope accuracy, when faced with typical line Voltage
swings. Naturally, most professionals use a variable auto transformer
(aka: Variac™) and a line Voltage monitor.


--
Trevor Wilson
www.rageaudio.com.au

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