General • Re: Problem with IRLZ44n mosfet in a circuit

Hi, thanks for replying!

- powering the pico from an external power source is usually done by using Vsys with a diode.
see https://datasheets.raspberrypi.com/pico ... asheet.pdf , Figure 16.
Apply power to Vbus can be done but conflicts with USB usage for programming.

I'm planning to disconect the battery whenever I want to reprogram my pico. I've done this before and there were no visible issues.

- batteries have internal resistance. Found various values in the net of around 1.5 Ohm. With 3A load current, this would mean the battery provides only half of its nominal voltage at this current.

Sorry, I wasn't very clear. When i measured the voltage between the drain and the source of the mosfet the steel wool wasn't connected (only a multimeter) so there were not a lot of current.

- at high current, the battery will deplete fast. 600mAh capacity at 3A empty the battery in 12 minutes (or something like this). I would propose to use two batteries for the circuit, one for the pico supply and the other for the power circuit.

I'm not planning for this circuit to run for a long time. So this isn't a problem.

To check the circuit, remove the steel wool and use a plain LED with a series resistor of 1k. Very small current, but immediately visible to see when off or on. If this works, then add the load.

I checked the circuit using a multimeter. (see attatched image)

Btw, what is the purpose of burning steel wool? Do you follow a tutorial found somewhere?

This is my first project using electrical components. And i figured i could make a timed igniter of sorts.

Statistics: Posted by H3LL_0U — Sat Jan 04, 2025 1:44 am

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