tlfong01 wrote: ↑Mon Feb 18, 2019 8:18 amDriving Big Motor Mabuchi RS-540SH 12VDC Motor
So now I have become a logic level Power MOSFET expert!
In order to build up my reputation, I decided to test the biggest motor in my junk box, the Mabuchi 12V 7,100rpm , 250mA (only!) motor.
I changed the 37GB motor by the big guy and switched on power, but motor not turning.
I removed the big motor and replaced it by the original small guy. But nothing happened. The solenoid and motor no longer responded. So now I am in big trouble!
tlfong01 wrote: ↑Thu Feb 21, 2019 3:58 amResettable PPTC Fuse vs Circuit Breakers With Manual Reset Button
However the shop there does not sell PPTC, but recommended a black thing with a push button. I have never seen such a thing before, but it is 15 yuan only, worth taking a risk. I bought it and found it a good toy, because is hand push button resettable. I think this is better than pptc fuse for testing power mosfet, because I know if there is overload, while pptc automatically resets, so I won't know if there is an overload.
tlfong01 wrote: ↑Thu Feb 21, 2019 6:45 amWhich Skills are Most Important on the Job and Which Skills are in Short Supply? - M Herk, CED, 2015
https://www.ced.org/blog/entry/which-sk ... n-short-su
Critical thinking and Problem solving stand out as the skills that are deemed essential to most jobs and are in relatively short supply.
PeterO wrote: ↑Sun Feb 03, 2019 9:42 pmYour analysis is flawed.That's only true for an unloaded GPIO pin. Assuming the GPIO is ideal is nonsense, and leads to nonsense results like it supplying 2.8A to charge the 1350pf to 3.3V in 1.6nS. That just isn't going to happen !
The GPIO pin is a voltage source which has a maximum source current as well, so you can easily workout a realistic rise time (it will be much longer that 1.6nS).
If sufficient resistance is added between the GPIO pin and the gate, such that the peak current is less than the upper limit, then the GPIO pin can be modelled as a simple voltage source making rise/fall time calculations even easier as it's a simple RC circuit driven from a voltage source.
tlfong01 wrote: ↑Fri Feb 22, 2019 2:36 pmBad IRF540N Still Can Pass 1.7A when Vgs = 5V
The cheap 1.2 yuan IRL540N, though not conducting at Vcc = 12V Vgs = 3V, can still pass 1.7A at Vgs = 5V. So it is still usable, with a gate driver such as optocoupler EL817C.
theitguyfromny » 2019-Feb-08 Fri 9:15 am
The FET was getting real hot before (too hot to touch), but not w/ the set up I have now, I don'think. I'll have to check again. I think it's because I was keeping the solenoid in its'open, non-default, position.
I have to believe there's ways to keep FETs cooler..but that's a different thread.
danjperron » 2019-Feb-08 Fri 9:39 am
If you read his last post it is not getting hot right now and this mosfet could drive up to 20A at 3V according to the speck.
tlfong01 wrote: ↑Sun Feb 24, 2019 8:27 amHobbyComponents IRF520 MOSFET Driver Module Model HCMODU0083 - £2.5
https://hobbycomponents.com/motor-drive ... ver-module
This little module is a breakout board for the IRF520 MOSFET transistor. The module is designed to switch heavy DC loads from a single digital pin of your microcontroller. Its main purpose is to provide a low cost way to drive a DC motor for robotics applications, but the module can be used to control most high current DC loads. Screw terminals are provided to interface to your load and external power source. An LED indicator provides a visual indication of when your load is being switched.
Schematic and Forum
http://forum.hobbycomponents.com/viewto ... =76&t=1872
ptimlin wrote: ↑Tue Feb 12, 2019 4:22 pmOK I have to ask, is tlfong01 some sort of weird automated BOT designed to analyse posts and then make up almost related responses, but not quite correct because a BOT doesn't truly understand what it is reading?There is nothing misleading about it. It is your misinterpretation of the spec sheet that is misleading.
tlfong01 wrote: ↑Wed Feb 27, 2019 8:02 am1kHz signal input to Power MOSFET IRL540N, Rg 470Ω, Rgs 4k7, Vcc 12V, Rload 5Ω 20W
Now I tested a 5 resistor 20W, and found everything OK.