Any clue about measuring nanoamps?

[user_1528391]

Hi, i'm trying to measure hibernate and stop mode current consumption at my Pioneer Kit. But i can not see the nanoamps with my digital multimeter(uni-t ut60e). I also have the opportunity of using an oscilloscope(Tektronix). How can i measure small currents lower than microamps?

[HeLi_263931 · Accepted solution]

Use a shunt resistor of the right value, and then use the milli-volts range of your Multimeter. Optionally use a current sense amplifier with e.g. G=100. As an example, looks at Dave Jones' µCurrent.

[user_1528391]

Hi hli, thanks for the reply.

   

I tried to use shunt resistor. If i use a small resistor, it works good. But i can not measure nanoamps if i use small resistor. So i tried to increment the resistance value, but if i use a big resistor the kit acts like the jumper has open-circuited. I mean the rgb leds turn off, kit stops advertising etc. I'm not expert at electronics, where do the jumper pins actually come from? Why does it turn some functions off if i use big resistor or if i simply remove the jumper out?

[HeLi_263931]

When the resistor is too big, the voltage across the it (when the PSoC is running with full power) is too large so the PSoCs supply voltage gets too low. Thats why you will need an amplifier (and thats what the µCurrent is doing).

[user_1528391]

That was a very clear answer, i understand it. Thanks 🙂