whats the best way to power arduino ???

my project is using 12v 5v and i need to power mega 2560 ???

mega as im aware uses 7v

i have a 12v 1a powerpack or a 12v 2a powerpack ??

im not clued on electrics so i ask you guys

how would i power put mega and them split voltage 12v 5v

Use the 2A supply as too much Amps is better than too few. (Remember that the rating in amps is the max it will supply not what it will push into your project under all circumstances.)

12 volts can be fed into the power jack of the Arduino (as long as you don't try to drag full current out of its 5v supply).

The 12v can also be fed into a 5v regulator to give 5v for the project if the current is not high.

Weedpharma

ty
im running on my mega at the moment

temp senor
light senor
2x lcds
relay x2
soliend thats 12v
high buzzer active
low passive buzzer
in total 6 leds

from the 5v

plus nrf001 wireless ( running from onboard 3.3v )

i have a 12v soliend that running of different power

like it all to run on the 12v 2amp ????

please can someone look at my diagram to see

first if my solenoid is setup ok

spec of solenoid
Square bevel latch
Input voltage: DC12V
Input Current: 0.6A
Instantaneous output power: 7.2W

second

how to i step down 12v to 5v so i can use lcds
not using the 5v from mega

added a better image please can someone tell me if this setup ok to use
what resistors i will need

also how to get 12v to 5v to use all 5v modules

and if this is the best way to power mega 12v outputs and 5v outputs

http://www.maplin.co.uk/p/ts2940cz-co-5v-1a-low-dropout-fixed-positive-voltage-regulator-n67ca

can it be done with this do i need any more

Does the LCD have a backlight? Usually that will draw 100mA or so from 5V. At that current, the voltage drop from 12v will mean the regulator on the Mega will dissipate 700mW, which is too much power for that little device. You can't power the LCD directly from 12v as it's got to be connected to the 5V Mega for data. (It may have a separate power connection for the backlight, but that's not very common.)

An external reglulator is necessary to provide the current required by the 5V devices. A 7805 is easy to get and has enough capacity for this. You may need to put a small heatsink on it but you can test it without the heatsink and see if it's getting too hot to hold.

Everything that is connected directly to the Mega should be on the same 5V supply as the Mega itself. It can be powered through its 5V pin.

again sorry if i didnt explain 100%

i have a 12v 2a powersuppy

12v 2a powerpack

i want that powerpack to run all mega lcd1 lcd2 soliend, led, buzzer, etc

so the 12v like soliends i use tp120 also the buzzer active on 12v with tp120

as shown in diagram helpplease.png

and 12v to mega

then i will need a regulator 12v to 5v to do all the 5v like lcd led etc...

my question is i brought ts2940cz from maplins first would that do the job and now do i connect (wire it up)
and what resistors sizes do i need

so i have 12v rail
5v rail
and mega powered

ts2940cz output voltage trimmed ( does that mean i dont neeed uf and resistors) ??

also would like be ok setup that way im not using the uno 5v for all modules ???

if someone could please look and let me know would be grateful, im sorry for nooby questions im learning

Looks good. Follow the datasheet recommendations for input and output capacitors for the regulator. Just pick any capacitor within an order of magnitude of their suggestion. 10 times bigger or 10 times smaller is close enough.

Stay away from the Fritzing diagrams. A schematic like your earlier efforts is actually easier to read.

thankyou just googled ts2940cz datasheet cant see about capacitor to use ??

12v = c? ts2940cz C? = 5v