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Topic: Atmega328 - Driving LED with P Channel Mosfet (Read 499 times) previous topic - next topic

ultrasound91

Now i must power on circuit?

bad_crc

#16
Jan 09, 2015, 06:22 pm Last Edit: Jan 09, 2015, 06:24 pm by bad_crc
I didn't understand
he mean that your R1 resistor should be connected between the gate pin of the FET and the output from your voltage regulator.    you have it connected to the gate pin and the low side of your R2 resistor which is not what you want.

 R1 is there to pull the gate pin on the pfet high ( turn it off ) when the 328 is not driving it
check out my arduino interactive LED table
http://forum.arduino.cc/index.php?topic=275263.0


Grumpy_Mike

I powered circuit. Led remains on.
So you take a meter and measure the voltage you have on the gate of the FET. If it is over 4V then your FET is broken or wired up the wrong way round.

ultrasound91

This is oscillogram of gate.

Grumpy_Mike

If it is over 4V then your FET is broken or wired up the wrong way round.
So guess what.

bad_crc

try a different pin on your arduino as well
check out my arduino interactive LED table
http://forum.arduino.cc/index.php?topic=275263.0

ultrasound91

#22
Jan 09, 2015, 10:30 pm Last Edit: Jan 09, 2015, 10:30 pm by ultrasound91
I confirm that mosfet are damaged. I replaced with a new. Problem solved. Thank you.

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