jumbo & segment 4 " display drive

Thread Starter

sathiyakumar

Joined Mar 28, 2012
3
i tried to lid up 8 (Digit) common anode seven segment jumbo display (4" size)using pic 16f877a micro controller in master and slave mode.

i used uln2003 for drive the segments and tip127 for source drive from controller.

every things ok when i lid 4 digits. but for all the 8 digits, the brightness reduced to half as before.

i am using PC SMPS 12v 5a rating.

please guide me solve the problem
 

bertus

Joined Apr 5, 2008
22,270
Hello,

Can you post a schematic and the code of the PIC?
Also a datasheet of the used displays will give more info.

Bertus
 

JohnInTX

Joined Jun 26, 2012
4,787
If you are multiplexing the digits, you will need to double the current into the segments when going from 4 to 8 digits to get the same perceived brightness.
 
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