an Arduino Duemilanove & Transistor Question?

[quant]

Hi,

The fact that this is a logical Mosfet and I'm giving it power rather than a logical 1 or 0 has nothing to do with it? It's a IFRZ4NN.

[quant]

This has nothing to do with IRFZ44N being a logical Mosfet or something?

[thatoneguy]

The Logic Level means that it will switch 18 amps with only 5V at the gate.

A standard mosfet needs close to the drain voltage at the gate to turn fully "on".

[quant]

Originally Posted by thatoneguy

The Logic Level means that it will switch 18 amps with only 5V at the gate.

A standard mosfet needs close to the drain voltage at the gate to turn fully "on".

Hi,

This seems like the kind of problem I'm having?!

Could it be that my Mosfet is not a logical one? How can I test that feature?

thanks

[bertus]

Hello,

What type mosfet are you using?
In your schematic you state IRLZ44N, wich is a logic gate mosfet.

Greetings,
Bertus

[thatoneguy]

Originally Posted by quant

Hi,

This seems like the kind of problem I'm having?!

Could it be that my Mosfet is not a logical one? How can I test that feature?

thanks

If the 5V and 24V supply grounds are separate, or other reasons causing the negative voltage readings, that is causing the issue.

What I'm trying to find with the measurements on the MOSFET while it is supposed to be on and supposed to be off will answer quite a bit.

While on, the voltage at the Drain should be very close to the voltage at the Source. If not, the gate voltage must be less than 5V.

When the black lead of the multimeter is on the Arduino ground, what does the +5V of the Arduino show? Without moving the black lead/ground, what does the +24 volt supply read?

Without meaningful voltage measurements, it is very difficult/impossible to troubleshoot.

[quant]

Noooooooooooooooooooo, My Mosfet is IRFZ44N and NOT IRLZ44N!!!!
Is that why?
No wonder they were cheap like $0.25 each!

Please Confirm!

[bertus]

Hello,

The IRFZ44 is a "standard" gate mosfet, and not a logic gate mosfet.
I attached the datasheets for both types for comparisson.

Greetings,
Bertus

[bertus]

Hello,

I have adopted the circuit for IRFZ44.



Greetings,
Bertus

[quant]

Bertus,

Thank you so much for the advice. Please recommend a type of Zener Diode also let me know if a IN4007 would do or not? Also any good readz on what a Zenner Diod does?