Thanks a lot for your help.So the 9V battery is struggling a bit at 7.4V, and about 6V across the 10 ohm, so 0.6A. 1.4V across the power FET and 0.6A, gives us about 2.3 ohm. But according to the IRLZ44N datasheet, with the gate voltage of about 3V, the part allows about 18A saturated and the equivalent resistance across it is under 0.1 ohm.
Clearly not a IRLZ44N. Could be an older power FET in the 5V gate drive class. We need a higher gate voltage for it to do anything. I guess you didn't buy the IRLZ44N from a place like Farnell.If this is the case, seller might have assumed that their buyers are mostly undergrads doing final year projects and maybe a Shenzhen guru says they are buying power FETs for some smart home demo running Arduino and they just need something 5V, laser mark these, save them some money and we'll make some money too -- it's a win-win...
I bought mine from a reputable local electronics seller, but oh well I guess that's how it is sometimes. I also measured the current that the battery outputs when being directly connected to the steel wool and it was 3.3 A max. So i think I will be replacing this defective IRLZ44N with irlml2502. I think this transistor's specifications are perfect for my application.
Statistics: Posted by H3LL_0U — Mon Jan 13, 2025 12:06 am