Switching Power Best Practice: Photon driven MOSFET's


I am a novice with all of the circuit design stuff, I just recently learned on a previous post of mine (here), that i can use mosfets to drive my components.

I have a sketched a circuit how i plan on wiring it up and don’t know if it’ll work. I have a 150 W power supply this one and want to eventually control a number of valves and pumps. I am starting with the most simple case, the adafruit plastic solenoid valve. I start with that one because i will have around 6 in total so i’d like to make it simple to add other components to be powered. Here is the first iteration of how i plan on doing it, please critique it and let me know it this will work. I don’t want to damage my photon or my house.

I have a linear voltage regulator between the power supply and the MOSFET, is this correct? What would be the best way to add another exact same valve that i’d like to switch independently.

No, that is not correct. That voltage regulator has a 5 volt output, but your solenoid is 12 volts. You don’t need that voltage regulator at all for the purpose you’re showing (you would need it if you’re powering the Photon with the same power supply). The way you have the power supply connected to the load and MOSFET is backwards. The positive side of the power supply should go to the load, and then from load to the drain (as you have it). The source of the MOSFET should be connected to the negative side of the power supply (the grounds of the power supply and the Photon should still be connected together).

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My mistake, i had ordered 12 & 5 volt voltage regulators and must have used the wrong model number, thanks for pointing that out. Is this something that would work for what i’m doing? Ive removed the LVT and fixed the connections.


Assuming its all good now, how would I say add three more of these? Do i run all of the components in parallel?

Not sure what you mean exactly by “in parallel”. You’d have another MOSFET hooked up to a different pin on the Photon, and it would be hooked up to the new solenoid and diode just like the first one.


I guess i should’ve phrased the question better. Since i have multiple components to switch do i run the power supply to rails then from the rails to each respective MOSFET. I want to ensure if a component fails that the rest of them aren’t in jeopardy.

Yes, that would be fine. The same for the ground.


Does anyone have any good resources for laying out protoboards? I find that doing it in frizing cant lay out four of the above solenoids without crossing wires. Am I just not thinking about it in the right way?