BUZ11 questions

[cobra1]

Hi

Never used mosfet in my life, so here goes

is there any reason to use a mosfet over a transistor?? From what i read the benifit is faster switching.

I was planning on using a BUZ11 for a set of led lights.
The total draw is 24v @ 4a, looking at the datsheet it can take 30+amps so i should be ok there

Another question is can this mosfet be driven directly from a pic output, from my reading it seems that Mosfets can work even if not fully open, will the 5v logic allow it to fully open???

 

[ben7]

BUZ11 is fine though you don't need a 30amp mosfet to switch a 4amp load.

I think it will be fine with a PIC but, you will need a resistor to keep your PIC from being damaged from high current going through the gate of the mosfet. Also maybe a diode to keep 24volts from going into the PIC if the mosfet transistor shorts.

Yes mosfets have a faster turn on/off time, and they also have a lower drain-source resistance when in the on state compared to BJTs.

 

[ronsimpson]

The data sheet....Gate turn on voltage could be as low as 2.1 or as high as 4 volts (typical 3 volts). But that is under one condition. Under high current you really nead more than 4 volts. If you build only one and use it at room temperature then it should work. I would never do this in production. Look at 'logic level MOSFETs'. They turn on at lower voltages. What supply for the PIC 5V??? not 3.3!

 

[cobra1]

Yeah im using 5v supply to the PIC, i have since found a IRL520 which is a logic level mosfet. Will get a couple and see if i can make them work.