Driving a N-channel MOSFET with a PNP transistor

[Systemz10]

Hi!

I am doing a project for an automated greenhouse. For the pump, heater, etc. I'm using a MOSFET to drive them. The circuit is attached. For the power I'm using a ATX PSU, Where the 5V power the arduino and sensors, and the 12V power the pump and everything else. I have 5 MOSFETS with transistor as show below on pin 7, 6, 5, 4. The problem is when i connect everything up and power it up the MOSFET is on no matter what the output on the pins are. I checked with my multi meter and i see that there is always around 2 Volts on the gates of the MOSFETS even when the 12V is not connected. I have no idea whats wrong and i would appreciate if someone could help me with this.

Thank you in advance.
Matt

[LarryD]

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[LarryD]

That is a NPN transistor, not a PNP.

Show us a good image of your wiring.

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[system]

Why don't you connect a logic level mosfet directly to the data pin?

[Systemz10]

ardy_guy:
Why don't you connect a logic level mosfet directly to the data pin?

I like to work with what I've got. And I don't have any Logic level MOSFETS.

[Systemz10]

There you go. The PCB.

[LarryD]

Do you have an image of a soldered board?

Edit:
Confirm you have all the jumpers installed (orange lines) and make sure all grounds go where they should use a DVM.
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[DrDiettrich]

In your circuit the MOSFET will be on by default, unless its gate is pulled low by the NPN transistor. As long as the PUMP signal is not driven high, the NPN will be off and the MOSFET on.

You can add a resistor, from the NPN base to +12V, to turn the NPN on as soon as the 12V power is on. But then you'll have a problem with turning this transistor off from the GATE input, due to the voltage divider formed by R11 and the added resistor. Remember that the base voltage then must become <0.5V to turn the NPN off. A 1M pullup resistor may work, eventually a bit less.

BTW I'd not trust a DVM reading in a circuit that is not properly powered up.