AC current vs DC current?
Great question! AC and DC stand for ’alternating current’ and ’direct current,’ respectively. Current means the flow of electrical charge from place to place. DC keeps flowing one way. If It flows a long time, that means that current flows around in a loop, always the same way. A battery provides a steady push, so battery circuits (like in flashlights) have DC. Alternating current (AC) is what you get from most wall outlets. It flows back and forth, switching directions. Most motors are designed to run off ac. Many electronic devices need dc somewhere inside, so they have devices called rectifiers that convert ac to dc.
What is the difference between AC and DC current?
We did a lab about this in science class and it has a bunch of questions we are supposed to answer at home. But I don't understand what the difference is between AC and DC. Like it's talking about a light bulb being lit by a battery vs. a light bulb being plugged into a wall outlet. I did look up AC and DC, but it still doesn't make sense. Thank youuuu!(:
If electricity were generated locally would (DC) Direct Current be better than (AC) Alternating Current?
dc is much to be preferred, if the devices to be driven are available at a sensible price in a dc form. Most small boats use 12 or 24v systems and devices such as refrigerators, freezers, dish washers, clothes washers and water purifiers are available in 12v. However, most manufacturers think that a 12 or 24v device is a licence to print money and charge the earth Wider demand in a different market (one not assumed to have money to burn) will probably correct that problem through normal market effects. If your load is dc all sorts of problems go away For example, if the sunlight comes and goes, circuitry capable of holding the voltage at the desired value whilst topping up from a battery is not complicated. However, in a local ac system the voltage, frequency and current available is subject to variation. In addition, the power factor and its complexities largely vanish with a dc source. It either has sufficient wattage (easily measured) to meet the total demands of the load or not, but that is not true in ac. You wouldn't be the first to connect an ac load to a local source to find the power available might seem to be sufficient but the load won't start up. The killing argument in the long run for very local distribution is that there is no such thing as a ac battery.
Why is alternating current better for long-distance power transmission than direct current?
AC can be stepped up and down in voltage very easily by transformers and the bigger the voltage the lesser the current. You tend to get less losses to resistance when distributing AC over long distances too. You can use thinner wires which means they’re cheaper to make and suspend.At the power station you can ramp up to thousands of volts and very little current through a step-up transformer. In the UK commonly seen voltages at the consumer end are 230V (residential, commercial, light industry) and 440V (industrial) and the same high voltages sent from the power station are ramped down again through a step-down transformer. In this way you get current back.It’s much easier to generate AC than DC too due to the way the generators turn.All in all, it’s better to have a cheaper system for the long overland haul of a national grid system where there’s miles of wire, lots of pylons to support it and the back infrastructure is minimal.That’s not to say you can’t or don’t do it with DC though. There’s one in Brazil that stretches for nearly 1,500 miles. Transmitting DC in this way is called, unsurprisingly, High Voltage Direct Current ( HVDC ). This is used in inter-country transfers; you can transmit HVDC into an AC grid of any frequency.Undersea cables are almost always HVDC because they act as capacitors, and being so long, big ones. AC would charge and discharge the capacitors and you’d probably end up using all the juice just in combatting the capacitance. HVDC charges it only when the voltage is first applied or changes. Strangely the one between England and the Isle of Man is AC. At 65 miles long it’s the longest AC underwater connector in the world and carries 90,000V. Why they chose AC I’ve no idea, there must have been some compromise between cost and technical efficiency but I don’t know what it was and it just goes to show.So it’s not a case of being better, it’s just that one is suited to certain circumstances more effectively than the other, and whatever the circumstances are you choose the system to fit.
Does DC current spark? If not, why?
Have you ever seen lighting? That's DC sparking. Electricity sparks (arcs) at 20,000 volt per inch no matter if its AC or DC. Usually DC sources are low voltage like batteries and such, so you don't associate DC with sparking, but it will and does. Static electricity is DC also. In fact the only reason AC current exist is because it's voltage can be increased by transformers so it can be transmitted over power lines for long distances.