how convert 3.3v from outputs digital to 9v ?????

Other Hardware General Electronics
1

how convert 3.3v from outputs digital to 9v ?????
i want to display num. on larg 7segment . it work at 9-12v . but the output digital from arduino is 3.3v . what can i use or do to convert this to 9v ?????

2

You need a driver like a transistor or a MOS fet or a chip like ULN2803.

But, we need to know more about your display.

3

thanks for your replay :

the display is 7 Segment 4.0" Com. Cathode (120 x 90 mm).

4

Do you have a web link?
Do you have a power supply for it?
Have you ever wired up anything electronic?
Will you be writing your own code to drive the display?

5

http://ram-e-shop.com/oscmax/catalog/product_info.php?cPath=152&products_id=1121

6

Where does it say "it work at 9-12v" ?

Do you have a power supply for it?
Have you ever wired up anything electronic?
Will you be writing your own code to drive the display?

7

i do tempreture sensor display the temp. on 7 segment . when i used small 7segment it worked very good . but when i connect larg 7 segment didnot work. becaus it want 9v but output digital is 3.3v

8

but when i connect larg 7 segment didnot work. becaus it want 9v but output digital is 3.3v

Just because the display is larger does not mean you need more voltage.

How did you wire up the smaller display? and what kind of display was it?
How are you wiring up the larger display?
Can you supply a pin-out for the larger display?

We need to see schematics.

It's time for bed :sleeping:

9

It's common cathode. All you need is transistors (or mosfets) driven by the arduino to sink the current .
Just insert the transistors between the current limiting resistor and the display anode pin and drive the
transistors (with series base resistors) with the arduino . It couldn't be simpler. (well maybe it could if
you used a dedicated 7-segment driver chip).