HOW TO USE MOSFETS

Tutorial Goals:

MOSFETs are a reliable and easy way to control the power for DC loads.They also work great for pulse width modulation applications like changing the color of an RGB LED. In this guide we show you how to use best practice for N-Channels.

Prerequisite Tutorials:

Understanding N-Channel MOSFETs:

SOURCE (GROUND):

The right-most pin is the "Source" pin. This line is where we connect the ground line that will complete the circuit for our controlled DC load. The load could be many different things, including lights, a motor, a heating element, and much more.

GATE (TRIGGER):

The left most pin is the "Gate" pin. If you are using a larger pottential load to switch the "Gate" line, it is a good idea to add a small (220Ohm) current limiting resistor to protect the MOSFET from a spike. It is however always important to add a 10K pull down resistor to protect against high impedance leading to false triggers. When a small DC voltage is applied to the line, the "Source" pin becomes connected to the "Drain" pin.

DRAIN (CONTROL):

Once the "Gate" line is HIGH and has triggered the MOSFET, whatever curcuit you have grounded to the "Drain" line will now be complete by its connection to the "Source" ground. If you are usins a motor or solinoid of any kind, it is also important to wire a flyback diode (schottky) in parallel with your load to protect the MOSFET from backflow.

Congratulations, you can now use MOSFETs to control DC loads!

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