A 1 digit seven segment display is a single LED consist of two terminals, an anode and a cathode. The anode is the positive terminal and the cathode is the negative terminal:
To power the LED, you connect the cathode to ground and the anode to the voltage supply. The LED can be turned on or off by switching power at the anode or the cathode.
1.2volt dc input power supply
2.20mAmps input current