What changes alternating current to direct current?

Answer 1

Because of the chemicals and metals which are used to make it, a battery can only produce dc (direct current).

For the same reason a battery cannot produce ac (alternating current) on its own, but it can be connected to another device, which is called an invertor, to produce ac for use by devices which require ac instead of dc.

Many of the devices and other pieces of equipment to which a battery can be connected will only work on direct current (such as, for example, car starter motors) but some things (such as light bulbs) can work on either dc or ac.

Some batteries are rechargeable but they cannot be recharged using ac . That is why all battery chargers which are designed to plug into house ac power sockets must convert the ac to dc.

For more information please see the answers to the Related Questions shown below.

Answer 2

The key is that the magnetic field in the transformer has to change. As the AC input voltage rises, the magnetic field builds up, as the voltage falls back to zero, the magnetic field collapses. The change in field strength is what induces the voltage in the secondary. DC current is constant, it does not vary with time.

Answer 3

Direct current flows in a single direction. Alternate current changes direction continuously - the current goes back and forth. In household current, there are either 50 or 60 cycles per second, depending on the region. In technology, other frequencies are used as well. For example, circuit for radio or television works with frequences in the MHz or GHz range.

Answer 4

When electricity is delivered to your house using power lines, most of the energy is used by appliances, lights, heating and air conditioning, etc. in your house. However, in the process of sending the electricity from the generating station to your home, some energy is also wasted in the power lines. This is an undesired but inevitable result of the resistance of the wires. Since the wasted energy is proportional to the square of the current, the power companies send power over long distances by using very high voltages and correspondingly low currents. Such high voltages would be extremely dangerous in your house, however, so the power companies use Transformers to "step down" the voltage somewhere outside your house. Transformers work only with alternating current (AC), and they essentially trade voltage for current. In other words, if the transformer drops the voltage coming in by a factor of ten, it will correspondingly increase the current going to your house by a factor of ten. This arrangement allows the appliances in your house to use relatively low voltage at fairly high currents, which is much safer than the other way around. Since the transformer is nearby your house, the resistive losses over that short distance are relatively small.

If not for the ability to step up and step down the voltage using transformers, power companies would either have to send electricity to your house at really high voltage (which would be extremely dangerous), or they'd end up having to generate much, much more power because most of it would be wasted in the power lines before it ever reached your house.

In addition to the fact that direct current (DC) cannot be stepped up or down in voltage, it has one other major disadvantage over AC. With AC, if you accidentally touch an exposed wire in your home, you'll get a pretty good jolt. It hurts a lot (I've done it a time or two), but it's usually not deadly because the voltages are relatively low (most likely 115-120V if you're in the US - usually less than 250V no matter where you are in the world) and your involuntary reaction is to pull your hand away quickly. In the case of DC, however, even though the voltages aren't that high, they are still extremely dangerous because DC causes your muscles to contract, sometimes making is so that you can't let go of whatever wire you've accidentally grabbed. With no ability to move, 120V DC is likely to be deadly.

Thus, AC is both safer and more efficient than DC when it comes to powering homes and businesses.

Or, answer B.

There are two common ways to change DC current into AC current. The first, and oldest, is the use of an electromechanical device that is a combination of DC motor and AC generator. The second, is the use of an inverter, which interrupts the DC to form a square wave. That is fed into a transformer and comes out as a sawtooth wave that can be used in place of AC sine wave in many applications.

Answer 5

Yes an AC can be converted into DC by rectification. Most appliances today have built in rectifiers to be able to receive incoming AC and change it back to DC when received.

Answer 6

A vibrator is to be used to conver dc into ac.

Answer 7

It sure can. It is just a bit more complicated than the other way round.

Answer 8

DC flows one way and AC flows two ways

Answer 9

Rectifier