Wiring the MOSFET Transistor

Introduction: Wiring the MOSFET Transistor

About: A combination of paradoxes, I love to create useless stuff of novelty. The less functional a project is, the more I'm interested in it. I like to inspire others to make things.

The MOSFET transistor is an easy way to allow your Arduino or other micro-controller to handle voltages larger than the 5 volts available for each pin. It's really helpful knowledge if your ever wanting to drive something that requires significant more power than a micro-controller can provide. I'm using it to control some 12 volt LED strips. I have also used it to control a salvaged windshield wiper motor. This simple circuit will open up more possibilities for your projects. 

Step 1: Parts

Parts list:
  • schottky diode
  • a MOSFET transistor (here I used IRF510) be sure the MOSFET your using can safely handle the voltage that your project requires
  • circuit board 
  • wire (three colors)

Step 2: Basic Wiring Steps

The MOSFET has 3 legs described as gate, drain, & source. Gate is the leg that receives the signal from the Arduino and is protected from the source voltage. Drain is the leg that is attached to both the power source (through a schottky diode) and what would normally be the ground connection of the device your trying to control. Finally the source leg connects to ground.

Step 3: Step by Step Wiring

Wiring this is relatively simple but for anyone who is just starting out I'll go through every step. First I strip the wire that will provide the power to the circuit. Placement is something that is important if your wiring several things to your circuit board. Here there is ample room for what I plan on wiring. Insert the wire into the board and solder. After that I insert the wire that will be for power to my device I also bridge the connection between these two on the circuit board. Then I bend the two ends of the schottky diode down and insert it into the board with the banded end away from the mosfet and then bridge the connection between it and the other power wires. Next I install the transistor on the board so that the middle leg (drain) is aligned with the un-soldered end of the schottky diode. The diode is soldered in place and the excess is trimmed off and the middle leg and the schottky diode are connected. Another wire is soldered in place next to this and connected to the prior connection, this will be what is normally the ground side of whatever your device is. A wire is soldered next to the source leg of the transistor and connected to it, this will be your ground connection. Finally a wire is soldered next to the gate leg of the MOSFET and connected to it, this wire is the wire that will go to the pin on your micro-controller that will communicate with the transistor.

Step 4: Connecting to Power, Arduino, and Device

 It is a good idea to check all your connections with a multimeter and confirm that all the connections you've made are connected and that there aren't any connections that shouldn't be there. I usually, just to play it safe, check the circuit with something at 5 volts or less to minimize any possibility of ruining my micro-controller. Once your confident that everything is correct, your now ready to control higher voltage devices. The MOSFET can also be used for PWM, enabling you to slow down a motors speed or to dim lighting. The project that I'll be doing will need two MOSFET so another one will be wired onto this board as well.



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    11 Discussions

    Just as a precaution, you may find it in your best interest to use a pull down resistor. The Resistor would be added to the Gate to ground of the micro controller. This is necessary so there is no doubt you have a low on your Gate if you send a 0 to it. This also will prevent any small leakage that can occur due to having a float.

    What Schottky diode would you recommend for a 12v 4amp light bulb?


    2 years ago

    Hi! Great tutorial--I have a few questions regarding MOSFETs and relays if you have some time to answer them.

    I see you attempted to get info on mouse over, which is very cool, but doesn't work that well for me. Is that a 4001 diode? Also, IDing the MOSFET terminals would be very helpful.


    Thanks for post. A schematic would be most useful.

    Guys need some help here . Im using a irf830 power mosfet to control a dc light , but for some reason i can't control the mosfet via the gate . The light turns on automatically without even supplying signal to the gate . I connected the source terminal to the negative of the battery , one side of the light is connected to the battery and the other is connected to the drain of the mosfet . I tried the same connection using a transistor and it worked fine . totally confused . need some help PLZ

    1 reply

    I think you are using a P-Channel MOSFET.

    Your soldering is hard to follow, you should use a bread board to show your connections or etch a circuit board. Also diagrams are useful.

    It was hard to follow your connections those single hole prototype boards (shudded).

    Anyway it wasn't bad just change the visuals. Bread board and diagrams will be a lot better. Not to mention odds are the newbie hobbyiest will be using a bread board.

    Fair observation, Schematics are hardly my strong point but I'll create one and add it.Sorry for not including one.

    Agreed!!! A wiring diagram would be most useful! I am new to mosfets and don't totally grasp it, but think a diagram would help. For example, why are the diode with rail power and power to the higher voltage device wired to the middle tab together?