Contents
What is an alternating current or voltage?
Alternating current (AC) is an electric current that periodically reverses its direction, in contrast to direct current (DC) which only flows in a single direction which cannot change sporadically.
What is alternating voltage in equation?
Key Equations
| AC voltage | v=V0sinωt |
|---|---|
| rms voltage | Vrms=V0√2 |
| rms current | Irms=I0√2 |
| inductive reactance | V0I0=ωL=XL |
| Phase angle of an RLC series circuit | ϕ=tan−1XL−XCR |
What is DC frequency?
DC has a frequency of zero. Direct current is the current that moves in only one direction and has a constant strength. An electrochemical cell is an example of direct current.
Why do you need an alternating voltage?
This is because generating and transporting AC across long distances is relatively easy. At high voltages (over 110kV), less energy is lost in electrical power transmission. Higher voltages mean lower currents, and lower currents mean less heat generated in the power line due to resistance.
Are volts AC or DC?
Comparison Chart
| Basis for Comparison | AC Voltage | DC Voltage |
|---|---|---|
| Definition | The AC voltage is the force that derive the alternating current between the two points. | The DC Voltage induces the direct current between the two points. |
| Symbolic Representation | ||
| Frequency | Depends on country. | Zero |
| Power Factor | Lies between 0 to 1. | 0 |
What are the symbols for AC and DC voltage?
The symbol measures the frequency of the object in the Hertz unit.
- DC Voltage. Represented by capital V with three hyphens and a straight line on top, the symbol stands for voltage.
- AC Millivolts. Represented by mV with three hyphens and a straight line on top, the symbol stands for milli-voltage.
Why is AC power transmitted at high voltage?
The primary reason that power is transmitted at high voltages is to increase efficiency. The lower current that accompanies high voltage transmission reduces resistance in the conductors as electricity flows along the cables. This means that thin, light-weight wires can be used in long-distance transmission.
Why is electricity AC and not DC?
Simply put, AC voltage is capable of converting voltage levels with just a transformer, making it far easier to transport across great distance than DC, whose conversion requires more complex electronic circuitry. Electric charge in AC periodically changes direction, causing the voltage level to reverse.