Hi
I have a question about measuring the current in a circuit
"" Why there is a big difference when I change from mA to A range in the same circuit ? ""
I have a 10watt LED and tried to find the current it derive and faced by this problem
I used tow DMM and the same result.
The voltage is the same in each try (8.11 V DC) .
The circuit should look like this
See the photos
First :- Mastech
At the mA range it reads 65.5 mA
At the A range it reads 0.14 A = 140 mA
So it is far away reading (140-65.5 = 74.5 mA )
The right side is the "mA range"
Second :- Fluke 87V
At the mA range it reads 108.2 mA
At the A range it reads 0.148 A = 148 mA
So it is far away reading (148-108.2 = 39.8 mA )
The right side is the "mA range"
I am thinking that the resistance of the DMM changes between the mA & A ranges .
So is my thinking is true ??
And which reading is the accurate to find the power delivered to the LED ??
Thanks