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Topic: 12v 5v power supply, and transistor question (Read 2575 times) previous topic - next topic

tigerbomb8


Why not buy a 12v regulated wall wart, and power the Arduino from it as well as the lights, through either barrel jack or the Vin pin? That way, you don't need to mess around with regulators.

Your schematic isn't right. You need to connect the -ve side of the 15v input to Arduino ground and the source terminal of the mosfet (and the ground terminal of any regulators you may be using). The resistor goes between the mosfet gate terminal and the Arduino output pin.
because the arduinos regulator can not supply enough current to run the LEDs and it would over heat

Grumpy_Mike

Quote
because the arduinos regulator can not supply enough current to run the LEDs and it would over heat

No the power to run the LEDs will not come from the arduino but directly from the 12V.

tigerbomb8


Quote
because the arduinos regulator can not supply enough current to run the LEDs and it would over heat

No the power to run the LEDs will not come from the arduino but directly from the 12V.

hmmm
i will still use the two regulators, it will  give me some good soldering practice and will ceramic caps work

CrossRoads

So you're gonna end up with this:
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

tigerbomb8

#19
Nov 29, 2011, 02:37 pm Last Edit: Nov 29, 2011, 02:40 pm by tigerbomb8 Reason: 1
well i wont need the resistor between the LEDs and the mosfet because i am using a pre-made LED strip.
with the resistor between the arduino and the mosfet what value should it be and with the caps for the regulators will 50 Volt Ceramic Capacitors work well.

P.S. the data sheet calls for 0.22uF and 0.1uF

Grumpy_Mike

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he caps for the regulators will 50 Volt Ceramic Capacitors work well.

Yes they are the best thing to use.

CrossRoads

Gate resistor: 100, 120,150, whatever's handy in that range
.22 & .1 are okay.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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