Do i need a travel adapter for a dell inspiron 1501 AC Adapter?

the input is 100 - 240 volts and in portugal they take 220 volts of electricity

Only adapter you will need for the computer is at the plug end for their type of socket. Can find them at hardware stores, computer parts stores and most major drug stores. Anywhere from $5 up. Main concern is current ability. A non-convertible hairdryer has a high current draw so make sure the power adapters are in excess of that if you carry one.