asking
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If your duty cycle is 25%, your peak current needs to be 4 times nominal. In other words, if the display is specified to run at 20mA, you need to drive 80mA into it when it's active.
Barry,
I Driving 4 seven segment selection using TIP122 now current is increased and displays are bright 2.5 times. Now total watt of Displays is 4.5 Watt which was before just 1.5 Watt 1 more thing i found....why our Displays were having Random nos. actually i haven't put capacitor to the LM7805 output so its was creating some ripple and which was affecting the displays input (PIC MCU)...while using transistors for switching..... so now problem is solved... But strange thing is that UDN2981 and ULN2003/ULN2803 are not affected, without capacitor also they were working perfect, i mean MCU was not affected.
Problem seems to be solved Thanks alot for your support.