Hi, I'm a beginner trying to construct project 09 with the motor and the transistor. When I attached a brand new 9V battery to the circuit, without the Arduino Uno plugged in, the motor was already powered. After some testing, I realised that the motor would turn off and on when i plugged and unplug…

Try this circuit with the LED instead of the motor to see if it works [image]

[image] trashcan08: project 09 Can you post a link to that? Not familiar with it.

Which starterkit? Please provide a link. Most of us don't know what project 09 is. Please try to find a link so we know what you're talking about. You don't seem to have a resistor between base (or gate) and the pin of the Arduino. There is a difference between a (bjt) transistor and a mosfet; yo…

Can you read the part number on the MOSFET? Does it have the number 540 or 520 somewhere on it?

[image] PaulRB: Can you post a link to that? Not familiar with it. For you and @sterretje Project 9 in Arduino project book [image] It's a bum deal with an IRF520!

The code for each of the starter kit projects are examples in the IDE. A parts list is included in the comments for project 09: /* Arduino Starter Kit example Project 9 - Motorized Pinwheel This sketch is written to accompany Project 9 in the Arduino Starter Kit Parts required: - 10 ki…

So is the MOSFET provided just a bad component in the case of an Arduino? Also thank you for helping me provide the schematics!

[image] trashcan08: So is the MOSFET provided just a bad component in the case of an Arduino? Yes. That MOSFET really needs a gate voltage of 10V in order to work correctly. Some may work OK with 5V from the Arduino and some may not. Plus the schematic is missing the gate resistor. That is …

[image] trashcan08: When I attached a brand new 9V battery to the circuit, without the Arduino Uno plugged in, the motor was already powered. The missing gate pull down resistor (say 10k to ground) could be responsible here. To test the mosfet, build a much simpler circuit to power a led. Yo…

Arduino Project Book code on github, project book in PDF, and IDE found here: [image] Arduino Projects Book Education You can find the projects in the IDE: IDE >> FILES >> EXAMPLES >> STARTER KIT >> (p02 through p13) The book exists here: The code exists he…

[image] sterretje: There is a difference between a (bjt) transistor and a mosfet; you're mixing the two terms I don't think @trashcan08 has mixed terms, so far, anyway. Seems to be using the correct terms for a MOSFET, and a MOSFET is a type of transistor! The T in MOSFET stands for transisto…

Problem with MOSFET in project 09

Official Hardware Kits Starter Kit

xfpd November 30, 2025, 2:44pm 11

Arduino Project Book code on github, project book in PDF, and IDE found here:

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Problem with MOSFET in project 09

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