MOSFET allows current through even when turned off

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Joined May 14, 2020

I'm relatively new to circuit design and I'm trying to create a circuit to turn on/off a 6V DC motor using a microcontroller. To do this, I am using an N-channel MOSFET. The MOSFET appears to be working, because the drain to source resistance when the gate = 0V is ~10 MΩ, and when the gate = 3.3V it goes to ~0Ω. Despite this, when the gate is set to 0V, the motor runs (with ~330mA). When I apply 3.3V to the gate, the motor runs a bit faster (~380mA). I can't get the motor to ever stop running. How is the motor able to run despite the gate being 0V and the drain to source having such a huge resistance? Circuit diagram attached.

Note I'm using a 5V source for the 6V motor because that's all I have access to. The motor runs fine at 5V.


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