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Direct current and alternating current can be easily converted into each other, yet they have essential difference
What is the difference between direct current and alternating current
For various applications and consumers, one needs either a direct current or an alternating current source. Among other things, it depends on whether the consumer has a polarity, i.e. a positive and a negative pole.
- Direct current or direct voltage – as the name suggests – ideally always remains the same. In a car battery, for example, there should always be about 12 volts between the positive and negative terminals during operation. Accordingly, this polarity (positive and negative pole) must also be observed for all connected consumers.
- An example of a consumer of direct voltage is a mobile phone. This is usually charged with 5 volts, sometimes also with 12 volts.
- AC voltage, on the other hand, is sinusoidal. This means that the voltage value oscillates between a maximum and a minimum value. As an example, the voltage can oscillate between 10 volts and -10 volts.
- Another important variable of the alternating voltage is its frequency. This determines the duration of the oscillation. The higher the frequency, the faster the oscillation.
- As an example of an AC voltage source, you can take the usual electricity grid. Here, a frequency of 50 hertz and a maximum and minimum voltage of 325 volts and -325 volts respectively apply in Germany. Consequently, the voltage between the connections of your sockets at home oscillates back and forth between 325 volts and -325 volts 50 times in one second.
- The more familiar voltage value of 230 volts in the home mains is the rms value of the voltage. This corresponds to the voltage value if the same power were provided by a DC voltage source.
- In an AC grid, there is therefore no polarity at two connections, since the polarity at the two connections – in the case of the German power grid – reverses 50 times per second.
