hello guys i made a circuit where every time i press a button, the uC sends pwm to a pnp for 3 sec., then pulls the base low again, and stays low until i press the button again. The point is that when the base is pulled low, the gate is pulled low. And when the base gets 3.3V, 75% pwm, the gate gets 5V, 75% pwm, the LED lights up for 3 seconds, then goes dark again.
And it works as expected. BUT when i substitute the LED,500ohm combination with a single 2.7ohm, the behavior changes. In the that case, the NFET will turn on 75%, but will not turn off after 3 seconds. it stays on until i unplug the power. I don't know why it will obey the uC when i have a LED, but not when i have a larger load.
And it works as expected. BUT when i substitute the LED,500ohm combination with a single 2.7ohm, the behavior changes. In the that case, the NFET will turn on 75%, but will not turn off after 3 seconds. it stays on until i unplug the power. I don't know why it will obey the uC when i have a LED, but not when i have a larger load.
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