I've been trying to learn about Mosfets and feel like I'm missing something important. By all respects they seem like a way to control higher voltages using the Arduino without having to worry about current draw form the arduino like you would when using a transistor.
But whenever I look at enhancement N Mosfets that come in multiple channels I almost only find common drains. What is the point of this??? Drain is what I connect my load up to, so why would I want to be able to a single load using two different gates on the Arduino?
Am I just misunderstanding how an N type mosfet is wired? Source goes to ground, Drain goes to load, and Gate goes to my Arduino, right?
I know I'm missing something, but I feel like I'm going crazy as I can't figure out what the benefit is from being able to turn a load on using two different pins on the Arduino.
Thanks for the response, but no it doesn't help I understand the basics of how to wire it and make use of it, my hold up is understanding why when it comes to multi-channel N mosfets why is that by far and large they tie the drains together?
I can find some multile N channel mosfets that have nothing tied together, it's rare but I can find N channel mosfets that tie source together (which makes sense if I'm using it as a switch), but why is it that most of them tie the drains together?
I'm thinking if I understood that, I would have a better knowledge of what mosfets are really useful for.
JCA34F:
Which MOSFET? There are hundreds. Post a part number.
Well I was asking about any given multichannel N Mosfet where the drains were tied together as that seemed to be the type I was encountering the most (ergo it stood to reason that this was the most commonly used type and there had to be a reason for that)... but to pick one at random, https://www.diodes.com/assets/Datasheets/ds31995.pdf
Now it might just be that as I was looking around I happened to hit only references to common drain type mosfets causing my beliefs to be skewed. BUT, if common drain types are the most, well, common there's a reason and I'm trying to understand that reason so I can better understanding mosfets.
JCA34F:
Are you confusing multiple drain connections with the common drain (source follower) amplifier configuration?
based off the included picture, I do not believe so. The ones I saw were all 2 gates, 2 sources, and a common drain between them. From my basic level searching I had come to believe this was common (as it seemed any time I did a search for (2 channel or dual channel N mosfet) the common drain was the one everyone was talking about. However, based on the responses here I'm starting to doubt that belief, lol.
That was the first time I had seen a configuration like that. I cannot think of a design that would take advantage of that.
I could see connecting the gates and sources together and just using it as a low Rds, Logic Level, SMD N-channel MOSFET.
I understand the basics of how to wire it and make use of it, my hold up is understanding why when it comes to multi-channel N mosfets why is that by far and large they tie the drains together?
