All public transport uses the OV-chipkaart. There's a one-hour card that can be bought on the trams from €2.70. You can get unlimited travel throughout Amsterdam on its trams, trains and buses for 24 hours for €7.50. Or use the card to travel for a week, or a whole season.
One-hour cards: Available from the conductor on buses and trams, at GVB ticket vending machines or GVB Tickets & Info locations
Multi-day and refillable cards: Available at GVB ticket vending machines or GVB Tickets & Info locations and select newsstands and supermarkets
When you start your journey, hold your card up to the reader until a green light appears. A beep sound will indicate that your card has been read. If you change to another bus/tram/metro, you have to check out and check in again at your next stop. about 5 years ago