I've ordered a handful of these, just to try them out:
They cost less than I could get the parts for locally.
But my question is:
Is 5V enough to reliably operate an IRF520?
It is sold for use with Arduinos and Raspberries, but according to the datasheet: http://www.vishay.com/docs/91017/91017.pdf the IRF520 has an RDS(on)= 10 V.
Further down it says Gate-Source Threshold Voltage 2-4V
They have not arrived yet.
Will it work with a 5V signal?
Am I overlooking something?
No.
The clue is in the name "IRF", you need something that starts with "IRL" - the 'L' stands "for logic-level".
That was fast!
Thanks
..... and just what I suspected!
I have some IRL540s, I might just change the MOSFET.
EDIT:
Looking more into it, I've realized that even though the IRF520 is not ideal, it will still let me draw up to 3 Amps.
That should be more than enough for most of the small disasters I'm building.
Peter_I:
EDIT:
Looking more into it, I've realized that even though the IRF520 is not ideal, it will still let me draw up to 3 Amps.
That should be more than enough for most of the small disasters I'm building.
If you look closer at figure 3 you'll see they had to apply 50V to get that current through it and they only did it for 20us.
The reason they only did it for 20us is that 50V @ 3A is 150 Watts of heat. ie. It will catch fire if you do it.
thanks again.
I'll play with them, but I will not have high hopes.
It really is a bad design not to put a logic level MOSFET on it when it is sold for microprocessor use!
Are the logic level mossies that much more expensive?
Peter_I:
Are the logic level mossies that much more expensive?
A $0.20 BJT will probably do most jobs that people are using $2.00 MOSFETs for.
They have arrived, and work OK so far.
I have tested them with a 9V DC motor and a 6V lightbulb.
The next must be a 12 V halogen and a windscreen wiper motor.
A little funny detail, by the way:
The "VCC" pin does not seem to be connected to anything, and it does its thing when SIG and GND are connected to the Arduino.
No, Vcc is there for the connector I think - you drive gate/source with a MOSFET.
MarkT:
No, Vcc is there for the connector I think - you drive gate/source with a MOSFET.
But it is funny that it is there.
I've tested for connection to every other piece of exposed metal on that board, and there is none.
That is simply too weird!
Its just a standard pin-out for a connector to an output, power/gnd/signal - if the
thing doesn't need power it doesn't connect to it, but all the cabling can be identical in
your robot or whatever.
MarkT:
Its just a standard pin-out for a connector to an output, power/gnd/signal - if the
thing doesn't need power it doesn't connect to it, but all the cabling can be identical in
your robot or whatever.
Aaaaaaaah, now I get it!
That makes sense.
Thanks