Hello everyone.I am new to all this stuff.Can anyone explain me the basic concept of multiplexing 7 segment displays using arduino?I searched a lot,but could not find anything which would explain from basics.So please explain it in detail with example.
I would be very thankful if anyone could.
Try this then
This video explains multiplexing very clearly 8)
Well I understood multiplexing by the concept of enabling.I tried it on ATMEGA16 using AVR studio.But in Arduino we do not have PORTA,PORTB,PORTC,PORTD.So how to enable the 7 segments when there are no separate ports?
Sure we do.
An ATmega328P (Arduino Uno) has PORTB, C, D.
An ATmega32u4 (Arduino Leonardo) has PORTB, C, D, E, F.
An ATmega2560 (Arduino Mega 2560) has PORTA, B, C, D, E, F, G, H, J, K, L.
The datasheets are your friends 
All ports/pins may not be available (due to use of alternate functions) or broken out to headers on a given Arduino model. For example, PB6 and PB7 on an Uno are used for the resonator that supplies the system clock.