All electricity supplies are a.c. D.C. is used, on occasions, for long-distance transmission (or undersea transmission) at very high voltages, but never for power supplies to homes or businesses.
dc power supply
Radios use DC power supplies to operate. If a radio is powered from a mains AC supply, a power supply circuit will convert the AC supply to DC. Therefore, a radio may have both a DC and an AC power input but ultimately, the internal circuitry will always use DC.
The type of power supply being used (AC or DC) should match the power requirements of the device it will be supplying power to.
DC 12V power supply can convert 110/220V AC power source to 12V DC.
A laptop runs on DC. Either from the battery, or the external power supply, which converts AC power to DC.
You can plug an AC computer into a DC plug only if you also have an inverter to transform the DC power into the AC power that the computer power supply expects.
The power supply in most cars is DC. The alternator may produce AC power, but it is then run through a rectifier, providing DC power.
If having DC and AC is required then a PWM pulse width modulator is required to chop the DC to make AC
It filters ac to pure dc
Almost all digital electronics use a AC to DC power supply. Digital electronics cannot handle AC. all electronics device having battery powered are using DC power supply http://www.wzmicro.com
Because equipment operating on DC is usually low-power electronic equipment, and it uses a power-supply to convert the house AC supply to DC at the right voltage. Most appliances needing high power are designed to run on AC because that is the normal supply to houses.
Batteries can provide both AC (alternating current) or DC (direct current) power, depending on the type of device they are connected to. However, most batteries themselves supply DC power. Devices that require AC power typically use an inverter to convert the battery's DC power into AC power.