Specific analysis of specific issues:
1. AC stands for alternating current. DC stands for direct current.
2. DC is generally coaxial, while AC is non-coaxial.
3. Power cables are generally AC, while coaxial cables for communications may be DC.
4. AC: Alternating current. This refers to a type of power supply with a fixed cycle or frequency. DC can be rectified from AC. It generally refers to power drawn from batteries and capacitors. Therefore, DC power cables are generally used for connecting the built-in power output of electrical appliances. AC power cables, if used for DC, can be used for DC power supplies with voltage levels approximately 1.5 times higher.
