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Topic: Trouble with transistor's (Read 529 times) previous topic - next topic

mcreefer

I've used the following 2 products numerous times
https://www.sparkfun.com/products/10213
https://www.sparkfun.com/products/10256

I always have trouble with product 10256.

But product 10213 always works perfect. I wire product 10213 on a bread board with this wire guide.
http://bildr.org/2012/03/rfp30n06le-arduino/

I used a comment on product 10256 to wire it. Comment is below.

Looking at this picture going clockwise starting at the very top left:
* The headlight's negative lead
* The headlight's positive lead
* Your supply voltage (The voltage/current your headlight needs)
* Gnd
* And Arduino IO pin
1 and 4 are connected through the mosfet. Connectivity between those two pins is controlled by 5.
2 and 3 are connected together directly, so they could be omitted.

Is there a reason for this? Am I wiring it wrong?

This is for PWM on 12V LEDs and fans.

l3gendluk3

I don't get whats wrong with 10256 (you wired it up wrong?). Also make sure you have a resistor on the arduino-gate line so you don't draw to much current and fry your arduino.

MarkT

Something like 180 or 220 ohm resistor between Arduino pin and gate will give best PWM performance and
protect the Arduino from gate currents.

I don't understand the difference - one is a MOSFET the other is the same MOSFET on a breakout board?

BTW what kind of fan are you PWMing?
[ I won't respond to messages, use the forum please ]

DVDdoug

#3
May 07, 2013, 01:54 am Last Edit: May 07, 2013, 01:59 am by DVDdoug Reason: 1
It looks like the same part, so you shouldn't see a difference.  What kind of "trouble"?    Is the LED/fan always full-on or full-off?   

This is a "wild guess", but I wonder if the resistor on the assembly helps prevent damage from static discharge, and the loose part is getting "zapped" during handling?

If the parts are dying for no apparent reason (not over-voltage, over-current, or over-heating), static discharge is a likely cause.

Once the resistor is "permanently" connected to the MOSFET, that would provide some static discharge protection.

fungus


I don't get whats wrong with 10256 (you wired it up wrong?)


Seems pretty difficult to wire it up wrong.


Also make sure you have a resistor on the arduino-gate line so you don't draw to much current and fry your arduino.


Yes, that resistor seems like a massive omission by Sparkfun - they ought to know better.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

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