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Topic: noob -> mosfets & solenoids (Read 939 times) previous topic - next topic


I'm trying to drive a air solenoid for a ping pong ball gun. I was recommended to use a IRFZ44N mosfet. I can wire the mosfet to my arduino and blink and led using the arduino's power supply for the gate and the drain. But when I try using an external power source for the solenoid it stays in the on position. Form googling around it seems that I need a diode between the terminals  of the solenoid but what type? solenoid is 12V @1A. Does my diagram look right ? 


The diode needs a voltage greater than 12V (pretty much all are) and repetitive pulse current rating greater than 1A.  Pretty much any '1A' diode will exceed these requirements, the common 1N4001 rectifier for example.

Alas your MOSFET isn't right, it needs 10V to drive the gate.  For driving from logic signals you should use a logic-level MOSFET.  There are work-arounds (use a NPN transistor to boost the logic signal voltage).

Most power MOSFETs are rated for 10 or 12V gate operation.  Logic-level ones can be recognised because the Ron value is specified at Vgs=4.5V or at 5V (not just at 10V).  People often think that if the threshold voltage is below 5V it will do  - but the threshold voltage is the Vgs at which the device starts to conduct (1uA perhaps).TLogic level MOSFETs have threshold voltage around 0.5 to 1.5V, not 2--4V.
[ I won't respond to messages, use the forum please ]


Hey thanks! Can you recommend me a mosfet ? Would a IRLZ44N work for my needs?


Hey thanks! Can you recommend me a mosfet ? Would a IRLZ44N work for my needs?

Yes that is a logic level MOSFET and will work fine. Many manufactures put the letter 'L' in the part number of a mosfet to give you hint that it's a logic level device. However the datasheet for the device is the proper place to determine if any semiconductor is correct for a given application.



Would a IRLZ44N work for my needs?

Yes  :)

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