Circle was designed with enterprising kids in mind and has an internal battery that will keep it working for 1-2 hours, even if it's unplugged. If you have push notifications turned on, you will even receive a notice when Circle runs low on battery power, or if it turns off from lack of power. If you notice that your Circle is sending notifications that it is offline or has low battery power, make sure to check that power cord! Since Circle uses a standard USB Micro port, feel free to use another charger or cable with it.
There may be times when you will need to turn Circle off. See How to turn Circle On or Off.
For more on notifications, see Notifications.