Problem on current drop at the beginning when MOSFET is ON

Thread Starter

wirtlon

Joined Aug 18, 2013
4
I am currently doing a project using the solar panel to charge up the capacitor to trace the IV characteristic curve.
I try to short circuit the load and everything then I only measure solely on the short circuit current.
However, when the MOSFET is ON, the current reading I get is limited at the beginning for about 400 milliseconds, then go up the exact value.

Anyone have any idea on why this could happen?
 

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Thread Starter

wirtlon

Joined Aug 18, 2013
4
What are you using to measure the current?
It may have some built-in delay.
I am using an ACS712 hall effect sensor to detect the current, the rise time for this sensor stated in datasheet is only about 5 microseconds, but the delay for my current flow is about 400 milliseconds.
 

Thread Starter

wirtlon

Joined Aug 18, 2013
4
And what capacitor do you have on the ACS712 filter pin, and what are you using to read its ouput voltage?
I had short circuit the MOSFET and get the reading and this shows a very nice short circuit current without any drop at the beginning.

I am using and external ADC, ADS1115 to read the output voltage of the sensor and pass to arduino to interpret.
 

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