How to measure verry smal current (amperes) with multi meter?
I'm trying to measure how much current can be generated from tomatoes.
Please have a look at http://maaikedevos.blogspot.com and my question will make a lot more sence.
What option should i use ( 200u, 2000u, 20m, 200m) if i use 20 on the voltage and i want to use the formula W=VxA ?
It seems to me that the measuring in itselfs alters the numbers. The brightness of the LED changes.
What is happening here ? How can i measure amperes ?
On the picture:
1/ LED hooked up to a battery. Multimeter placed in series to measure the current. (the LED seems to light up but this is reflection)
2/ I turn the multimeter to 200m, the LED lights up very brightly. On the display: 03,8
3/ Multimeter is turned to 20m, the LED lights up. On the display: 3,29
4/ Multimeter is turned to 2000u, the LED lights up. On the display: 1197
5/ Multimeter is turned to 200u, the LED lights up but not verry strong. On the display 1 .
Thanks to any one who can explain this to me in clear language. This are my first staps in elctricity-land.