how to change DC current to AC current ??

Answer 1

white out

Answer 2

Inverters use DC and turn it into AC by using switches (transistors) to rapidly apply DC voltage to the load to approximate the AC waveform. The DC must be positive and negative, which is necessary because if you recall, AC (alternating current) is switching from a positive to a negative voltage so as to give the alternating current.

Going from memory, the period of 60 Hz AC is 16 milliseconds. During the 16 milliseconds, the switches (transistors) can switch from 1000 to 10000 times (the engineer picks a fixed frequency based on a number of factors).

During the positive AC cycle you are trying to create, the switches (transistors) apply positive DC pulses to the load. During the negative AC cycle you are trying to create, the switches (transistors) apply negative DC pulses to the load. The length of time the DC is applies determines the magnitude of the AC waveform. So for the zero crossing of the AC waveform, the DC will not be applied at all, and at the AC peaks, the DC will be applied for the longest time (it can't be too long, or it will saturate whatever you are powering, often a transformer or motor). To get real AC (that doesn't look chopped up), your load must have some inductance or capacitance on the input to smooth out the DC.

The inverter I just described is a better inverter than most. Cheap UPSs like APC desktop models apply sucessive square waves in a stair step pattern, and as a consequence, the AC is not that great, but good enough for computers, which rectify the AC back to DC anyways, and have large filter caps.

Better UPSs (inverters) are the online type, because the inverter is actively powering your load. This gives good protection against surges. Almost as good are the line interactive type. The cheapest are the offline (which means your computer is connected directly to the utility until a power loss, when your computer endures a short brownout while UPS switches to the inverter. This UPS uses MOVs to protect against surges, but MOVs wear out after repeated surges. You get what you pay for. Liebert UPSs are the best as far as I am concerned. They might be a little more expensive, but you get what you pay for.

Answer 3

An UPS system does this all the time, it can take a DC battery and produce 120 Vac. Is this what your are asking?

APC makes many different size UPS one for your home too.

UPS is a power supply that will produce AC current from DC batteries when there is no AC power applied to the system. Its a common back up power device.

Answer 4

Buy an Inverter. Just search google for one.

Answer 5

you need a conveyor

it all depends on how much you need

Answer 6

CAPACITORS CAPACITORS AND CAPACITORS