Power and signals are the two broadest categories of electrical phenomena in every electronic device. Power from an AC outlet or DC battery is the energy that makes it work, and the signals are the data being transmitted. See
AC,
DC and
signal.
Smartphone Power and Signals
In a smartphone, power comes from a DC battery and the signals are the bits and bytes transmitted externally via cellular, Wi-Fi, Bluetooth, NFC and GPS. See
smartphone.
Computer Power and Signals
In a computer, power comes from an AC outlet or DC battery, and the signals are the bits and bytes transmitted via Ethernet, Wi-Fi and Bluetooth.
Make a Powered Speaker Wireless
Google's Chromecast Audio, which was on the market from 2015 to 2019, plugged directly into a powered speaker's audio input. Like countless electronic devices, it required power and transmitted signals. (Image courtesy of Google Inc.)