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A unidirectional flow of electric charge is known as a direct current (DC). The most important example of DC is an electrochemical cell. Direct current has the flexibility to flow through conductors, mainly wires. The only difference between DC and alternating current (AC) is that it flows in only one direction. Galvanic current is the term used for this current.
The frequency of DC is zero (0 Hz). This is because of the flow of electric charge in one direction. As there is no way for any reverse in the direction, the frequency of DC always remains zero.
Differences between AC and DC
Circuit of direct current
The electrical circuit that consists of constant voltage sources of any combination, resistors, and sources of constant current is known as a direct current circuit. This circuit’s currents and voltages are not dependent on time. The particular current or circuit voltage does not depend on the past value of any current or circuit voltage. The integrals or derivatives respective of time are not included in the equation that implies a DC circuit.
When, in a direct current circuit, an inductor or a capacitor is added, the circuit which is formed is not a DC circuit. But this condition has a solution. When the circuit is in a DC steady state, the solution gives the currents and circuits voltages. A differential equation represents this kind of circuit.
Sources of direct current
Many sources of direct current are very important and useful in our day-to-day life. Some are listed below:
Dry cell batteries
Solar cells
Commutators
Chemical cells
Dry cell
D.C. generator
Car battery
How to calculate the frequency of direct current
The frequency of DC is zero hertz because DC flows in only one direction. So, now, if we calculate how this zero is obtained, we will know how to calculate the frequency of DC.
Frequency = no. of changes/second. Therefore, it is the number of times the voltage changes. A pure DC remains constant. Therefore, the number of changes is 0 and 0/sec = 0. After this equation, we know how to calculate the frequency of direct current. When a graph is plotted between time and frequency of DC, the results come out as a straight line. Thus, the frequency never changes. Now, when we talk about a non-pure DC and a single-phase full-wave rectifier which forms a wave that is unfiltered DC, then it will consist of some frequency at the top points. Thus, when it is an unfiltered DC, there are chances of frequency ranging up to 1.2Hz.
Usability of direct current
Direct currents are a widely used type of electric current. They are used in:
Commercial buildings and domestic houses: DC is used in the houses for low voltage applications. These are generally powered by solar systems and batteries. These applications generally include batteries, wall sockets, and switches. But direct current consumes more power than alternating current.
Telecommunications: For this process, the equipment which is used is called telephone exchange communication which uses a standard -48V DC power.
Automotive: Maximum automotive applications use direct current. It is a battery that helps in engine starting and lighting. An alternating current device, known as an alternator for charging the battery, produces direct current by using a rectifier.
High-voltage power transmission: Direct current is used by the high-voltage direct current electric power transmission system. By using the direct current, it conducts bulky transmissions of electric powers. The HVDC system may be less expensive and can cause low electric mishaps for long-distance transmissions.
Conclusion
Direct current is a type of current that flows unidirectionally. A direct current can flow in a circuit when the circuit is closed. But when the circuit is open, the flow of current stops. A power source is required by a simple circuit where a certain amount of voltage has to be supplied. Wires are also needed to connect the components. The circuit is monitored by an open and close switching system. There is a potential difference when voltage is supplied in a direct current circuit which causes the flowing of current. The supplied voltage is directly proportional to the current. This relation is defined by Ohm’s Law. Direct current is used in many applications like telecommunications, automotive, domestic houses, etc. for a budget-friendly and low voltage facility.
