Nice to meet you all. I am new on this forum (french so please forgive my possible english issues^_^). I am also new on electronic things and my domain is usually more mechanical engineering stuffs.
I have an issue, and despite lots of researches I still do not find precise answer to my questions.
The topic is quite common, command a 12v motor using :
- 12v alimentation
- MOSFET N channel IRFZ44
- Arduino Mega
To summarize, hardware side: - Gate is linked to PWM compatible output of the Arduino (PIN11) - Drain is linked to the motor - Source is linked to the ground
What happens? :
-When I have 0% on PWM signal, that is to say 0 over 255 on analogWrite command, 0V for motor, this is OK - When I have 100%, 255 over 255, motor has 12v, so this is OK too - When I have <1%, or 1 over 255, motor has around 7V and this is the issue - When I have 50%, so 127 over 255, motor receives around 9v.. so quite linear if we consider that starting point is the 7v above.
I have read that I should have resistances between ground and gate to pull down (10 kohms) and between the Arduino PIN and the gate (100 ohms) but nothing changes.
I have tried with :
- 2 different arduinos
- with or without resistances and with several values (10k, 100k, 1M for pull down, and 20, 100, 200 for the other one)
- 2 different MOSFETs
I have seen that tension between PWM signal at 1% and ground was 0.5v, maybe this is a clue? It seems quite high...
I have also read Vgs tension is crucial (logic TTL MOSFET existancy) mine is equal to 10v in the datasheet (seems to high for my Arduino) but finally some other topics say that this is ok because Vgs (th) is 2v mini so Ok for Arduino (and his 5v). As I reach the 12v when I am at 255, I guess that this MOSFET (IRFZ44) is compatible with Arduino PIN?
In conclusion, I am a bit lost with all of this. I really need your help to progress on this topic. :confused:
Really thank you for your help. :) I am aware that this is something that should be easy but I do not find the solution.