Question

The frequency of a direct current (DC) is
A. $0Hz$
B. $25Hz$
C. $75Hz$
D. $100Hz$

Answer 1

Hint: Direct current is a type of electric current that is unidirectional. Due to this all charge carriers always flow in one direction only. DC current can be obtained through AC current using half-wave and full-wave rectifier circuits.

Complete step by step answer:
The value of voltage is constant over time in the case of a DC source. The following diagram represents the waveform of DC over time.

As DC is unidirectional it moves in one direction only and gives a constant output.
The DC current can be achieved by the rectifier circuit. There are two types of rectifiers. One is the half-wave rectifier and another is the full-wave rectifier.
A half-wave rectifier converts only the half-cycle of an AC source into DC output. On the other hand, the full-wave rectifier converts the whole sinusoidal cycle of an AC wave into DC output. Nowadays all the instruments or home appliances such as TV, refrigerator, etc which work on DC source have a rectifier attached to the circuit only.
Thus, from the above discussion, we can say that the frequency of the direct current is $0Hz.$

So, the correct answer is “Option A”.

Note: DC current is very easy to store for a long time. All the batteries and power banks give a DC output. Nowadays all the appliances are powered by DC supply. But we have a restriction in the use of DC current that it cannot be transferred for a long distance of time. Thus, in transmission systems, AC current is used.