When you simply ramble a bit and share your real world experience you make significant contributions to my students. More than one has done the "see, I told you" thing. It is truly nice to have some unscripted stuff on KZfaq. Yes, yes, the well scripted has its place too. But don't stop just talking about how things really happen.

But were you driving them with pulse width modulation? I had a P-channel mosfet powering a windshield wiper motor. (My RDS on was 3 milliohms). With the gate at full negative potential, didn't even need a heatsink. As soon as I drove it with PWM, heating was a big issue. The gate current to charge the internal parasitic capacitance meant that there was a "ramp-up (and down). A possible 200mA (from a 555) was not enough to drive the gate. Further research showed that there can be AMPS of gate current to charge the capacitance. (in my case, around 13,500 pF). And it appears that mosfet driver chips are available to overcome the problem. I am going down that road now... So, were your "dodgy" mosfets actual getting ramped on as a result of a high gate capacitance and insufficient drive, or were all your tests at DC? Regards, and good luck.

Hi Lewis love your vids thank you... I have had this problem with E bay silicon fake irfz44 and the like...

For arduino's with 5v logic, I use IRL540's, with a rDS of .077 ohms and a Vgs of 5v.

What can we do if our load requires a voltage lower than logic level? For example I want to control a 3.7v motor with Arduino, will a bjt more effective?

yep, do not source your parts from ebay for designs like this. Love your work Lewis!

Because of questions using MOSFETs I tested a lot of them. Here are the results. Added the following related videos: N-Channel MOSFETs Test Results, Observation kzfaq.info/get/bejne/qMCPjc14ut3Zcac.html Parallel P-Channel MOSFETs Results, Observations kzfaq.info/get/bejne/e5OCmrljx92Zj58.html

very well explained

Am having heating is with my pwm the mosfet getting hot in 1 hour of turning on at 6 amp the capacitor valve is correct so am thinking the new components or manufacturing is bad all of my mosfet burn out on 1 amp and the pwm just never turn on with the second circuit I made and all 5 555 Ic just won’t turn on in pwm so am thinking if I use a pin holding Instead of the welding to the pcb so I will see if it’s the welding heat that burn something inside but I only have one working pwm for 10 Ic all 9 was bad the capacitor valve is 1 uf

Good video

Here is solution: use voltage 20 v on gate of transistor mosfet .... and before that use pc817 uptocopler .... to control transistor.... it’s very easy I try it many time and working great up to 40 amp .....

sir,will there any #permanent #change in threshold voltage or RDs ... if mosfet is running hot all the time ?? please reply

👍👍👍

The IRFZ44N has come in handy for me. Rds on of .02! or less (.0175) Not bad, there are much bigger etc, but it covers a lot. Just my opinion, good video.

I bought a 50 pack mosfet and all of them or heating up fast in my inverter circuit the frequency is 60khz and i adjusted it all the way to from 1khz to 600khz and heating up as fast it’s on and burn up the transformer is a big 28-28 volt I try all type of frequency I’m my own drive and I can get the mosfet to work cool and stand on i even us a old inverter driver and the mosfet get hot as it on I bought some irfz44n and the same thing happens so am wondering why this having even with a manufacturer inverter drive it’s burn up

pls.. pls.. help to my project sir.. my mosfets gets hot... and my stepper motor vibrates.. does the switching speed of a mosfet needed to be considered? and how to check switching speed on the data sheet? my design it amplifying signal from a stepper driver allegro.. thanks a lot in advance..

What about High Power High Voltage MOSFET Modules by Vishay

Hey! I have many components purchased from EBay I hope I didn’t burn that doe for rubbish!

Yes ebay stuff is usually but not always factory seconds . Buy from a reputable supplier and if you find that the components are out of spec you should get a refund or replacement.

isnt Rds on dependent of temperature?

Well I don’t agree if your mosfet is fully on and fully off the voltage drop is 0.9 volt your circuit is not is order the circuit missing a lot of temperature control when you using high and low gate drivers Ic or emitter follower use a pnp bjt to sink the gate fully on for n channel mosfets to fully on and fully off npn bjt to turn off p channel fully of and fully on I don’t have this issue, because when I was learning about gate drivers and low side gate drivers and high side drivers what i discovered is that when I use the driver only the mosfet would heat up badly and even if I use a 10k resistor the mosfets would still get hot and for months I try different methods and the only method that works was bjt as a voltage sink and it work to my surprise the mosfets was turning on fully and off fully with dead time in sink with rising and the mosfet never get even warm at 200 watt without heat sink for 3 minutes and then it get warm because of amperage passing and with 1000 watt and heat sink with fan cooling the temperature rises to 48.6 degrees c so just remember resistor won’t work only bjt can do the job

where to buy non fake mosfet

AT 3:40....you claim that is a P channel. Shouldn't that be a N channel because the arrow points away from the gate