What manufacturer? IRFZ44N From Infenion/International rectifier has 17.5 mΩ max at 10V (typical is lower than that even for NXP part) VGS https://www.infineon.com/dgdl/Infineon-IRFZ44N-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a40153563b3a9f220d Another thing is that they may sell a part with lower VDS which automatically makes RDS go down for the price. I'd at least measure gate capacitance to see if it's anywhere close to the real part. 40 mOhms at 5V VGS likely means fake with a very small die but made on a more modern process (poor SOA in linear region), I would expect more resistance from a genuine part at 5V VGS. Also you use multimeter with insufficient resolution, and as they round to the low side (unless there is a positive offset) it easily can be anywhere in 0.2-0.3 mV region. Not that you should ever trust the last digit to begin with. As your meter should have tolerance spec something like 1% + 3 least significant digits (although it's garbage enough they don't mention digit tolerance spec at all https://cdn.shopify.com/s/files/1/0268/7746/0673/files/01DMMAS830.pdf?v=1625849553 EDIT: Mastech that actually makes it has it https://mastech-group.com/as/en/MAS830B ±(0.5%+3)). You need either more current or a better meter to measure this.
Agreed, I need a better measurement. I tried again running 169.6 mA through it and got 4 mV across the Drain-Source. The math comes out to be just over 23 Ohms
Now here is the caveat to all of my measurements. Yes, I don't have the greatest test equipment. The multimeter that you were picking on was not one that I chose, but one that was given to me.
That also means: no I do not have a power supply that can handle the current ratings that the IRFZ44N can handle. Nor do I have an LCR meter. This is all to say that I am limited in what testing I can do.
This also means that I cannot match the test criteria put forth in Infeneon's datasheet exactly: I
D = 25A, Pulse width ≤ 400µs, duty cycle ≤ 2%. This means any measurements I took must be taken with a grain of salt because they may be worse, or may be better.
So the part could be out of spec or it could be within spec according to my measurements, all I can tell from my measurements so far is that if the IRFZ44N that I bought is out of spec at all, it is not hugely out of spec (as insinuated) at least as regards R
DSSo I am pretty much at the limit of my testing when it comes to V
DS I
D or R
DS. If someone else with better-suited test equipment wants to give it a shot go for it, but I doubt anyone has the guts to because it means biting the bullet and buying the components, around which there has been so much insistence that they are fake.
Let me put it this way:
Wraper, so far all I have heard from you (and most other people so far) about this company is slander: absolutely no personal experience with this company and yet somehow a self-declared expert. Instead of trying to tear down a company that this is probably the first you have heard of, just for superficial reasons (selling on Amazon, the pictures they use, etc) and with
absolutely no hard facts of your own (and even worse: asserting your pre-conceived opinion as fact), consider getting your own data.
There is a saying that "if you cannot say anything nice do not say anything at all". Well, while I do not think that is always a rule to go by, here is something that one should always go by: "if you can't say something that you know for a fact, then don't present anything as fact".
Yes: the fact is there are tons of fraudulent Amazon companies. I agree with that fact.
And maybe the EEEEE store is one of them; I am by no means saying that the EEEEE store is honestly selling components up to spec. All I am trying to do is make sure the information shared is objective fact and not some random person's pre-conceived opinion.
In response to:
...and due to people like you it's hard to buy some obscure, obsolete, or just discounted NOS components without being duped...
Perhaps it could be said that it is because of people like you that any honest electronics shop on Amazon does not survive.