Hello, I am looking for expertise on MOSFETS. I am confused as to how to use the drain on a mosfet. I am trying to control an IRF520 MOSFET module with my Arduino uno. I would like to be able to control the output voltage of the mosfet from 0-12 volts and and any point in between. First off Is this possible or do MOSFETS only work like a switch 12v or 0v no in between. Second if it’s possible how do I control the output Voltage of the MOSFET? Thanks In advance I’m new to this and appreciate any input!
Poor choice.
This is not a logic level mosfet and shouldn't be sold for use with Arduinos.
It will only work for light loads, and yes, it can only work as a switch.
Also because the Uno has no analogue outputs.
If we knew your intentions then we might be able to point you in the right direction.
Leo..
You can use PWM (see the IDE examples) and control the average voltage, or find a FET that matches your requirements which can be very hard to do. There are many different types of FETS. Like Wawa said, please give us details on what you want it to do.
I would greatly appreciate it if you could assist me in the right direction I am completely new to this and I am lost there is so much to learn. The project I’m working on is controlling a VGT solenoid. The solenoid functions on PWM 12v and is controlled by increasing and decreasing voltage. I need to be able to control the solenoid at any voltage between 0-12v. I am using a pressure transducer which operate
0.5-5v output connected to my Arduino uno. When the pressure sensor reads 0 psi I would like the solenoid to get 12v power. 5PSI = 10.5v 10Psi=9 v 15psi= 7.5v until 40psi 0v, you get the idea? If you could please point me in the right direction on how to obtain This it would be greatly appreciated!
Start by working through some of the simple examples in the Arduino IDE. Learn to blink an LED without using delay(), read a voltage, read a sensor, etc. That way you learn some of the special features of the Arduino, and get a start on learning the programming language.
Any other approach, except for hiring someone to do the work, guarantees endless frustration.
This sentence is a little confusing. PWM basically switches the power on and off at whatever voltage you're using so that the average voltage changes. 12v on for 50% of the time reads 6v. That's not exactly how it works and it's more complicated than that, but close enough for the idea. A logic FET would work in this example.
You need to find out for sure if the VGT is PWM, or analog voltage controlled. Analog voltage (compared to PWM average voltage) is kind of like a battery. It's a constant voltage. E.g. 6v, 12v, etc. For this you need a FET or BJT that can handle whatever amperage load is required and scale according to the input voltage. For that you'd need DAC (digital to analog) output, which as stated the UNO doesn't have. So you'd have 0 - 5v (or 3.3 depending on the board) DAC and your FET would scale its output voltage according to your DAC input. It's harder than it sounds though.
This is something I found on how the solenoid actuated “ With a constant battery voltage supply to the VGT actuator, the PCM completes the circuit through a driver which is simply a transistor capable of handling the voltage and load. The higher the Pulse width value, the longer the valve stays open... thus the further the actuator will travel. sorry I’m still learning all of this, so what I’m understanding is I need to supply a constant 12v to the solenoid and I will control the position of the solenoid by adjusting the frequency of the PWM?
If it’s not the correct frequency which I don’t think it is I think it’s low like 25-40 hz and I think Arduino is 960hz. Is there a way to change the output frequency from the Arduino? And if not what are my options for a controller that does
FYI - That is possible... But for certain applications, like variable-control of a solenoid, controlling the speed of a motor, or dimming a light bulb it's not the best solution.
In applications like audio amplifiers, MOSFETs & transistors are normally used linearly (1). The circuit is more complicated and more finicky. Like everything else, MOSFETs have tolerances & variations so they don't all have the same gain. So for example, if you want a gain of 10 you have to design the amplifier circuit so you always get that gain even with the part variations.
Often more important - When you use a MOSFET or transistor linearly it has voltage across it, and current through it at the same time. Power (wattage) which creates heat is the combination of current & voltage and it's calculated as Power = Voltage x Current. The MOSFET or transistor heats-up.... You might need a heatsink and/or a bigger MOSFET and it's not as energy efficient.
In a switching circuit, there is virtually no current when it's switched off. And when it's switched-on there is very little voltage across it. Without current and voltage at the same time, it runs cooler, can handle more current, and is more energy efficient.
The switching-time can be fast (sometimes MHz) but the switching-time isn't instant... It's partially-on for a brief period of time and that generates heat and if you switch it very frequently it gets hotter.
A regular-old on-off switch or electro mechanical relay is even more efficient... The light switches in your house stay cool whither they are on or off. But they can't switch hundreds or thousands of times per second.
(1) In a class-D audio amplifier the MOSFETs are switched similarly to PWM. But the switching is smoothed-filtered to get a nice controlled analog AC voltage.
With switching power supplies & switching voltage regulators the switched voltage is filtered to constant-smooth DC.
Quick question, if I were to remove the IRF520 mosfet from the mosfet module could I solder in the MOSFET you suggested to the module and it will still function? I also have had no issues with driving the gate of the irf520 mosfet with 4.5v from my Arduino Should I still switch to the suggested mosfet you showed me? And last question shoukd I get a heat sink for the mosfet?
Quick question, if I were to remove the IRF520 mosfet from the mosfet module could I solder in the MOSFET you suggested to the module and it will still function? I also have had no issues with driving the gate of the irf520 mosfet with 4.5v from my Arduino Should I still switch to the suggested mosfet you showed me? And last question shoukd I get a heat sink for the mosfet?
The load evidently does not draw enough current for you to see the problem. If the project works and the MOSFET is not too hot to touch, no worries (with that particular load).
The IRF520 is not guaranteed to be fully turned on with gate voltages below about 10V.