In this article, we will explain what is current, current unit, and types. To better understand the concept of current, if we briefly explain the concept of the conductor. Some substances allow electric charges to flow through it. These substances are called conductors. One of the best-known conductors is copper. Copper conducts electricity very well; because the electrons of copper atoms can easily move away from atoms.
In a piece of copper, atoms are arranged in regular rows and columns called lattices. Electrons moving away from atoms move freely randomly in the space between copper atoms. If a battery is connected to the ends of a copper strip, the negative end will give electrons to copper. The positive tip collects electrons. So electrons are attracted by a positive charge.
What is Electric Current?
Electron flow through the copper strip is called electric current. The electron flow is from the negative end to the positive end. In electronics, we usually consider the current flowing from the positive end to the negative end. The current travels through a circuit. It flows out from the positive terminal of the battery and returns to the battery through the negative terminal again.
The same amount of current flows through all parts of the circuit. Although this was not an actual event, many people found it more useful to accept it in this way. The principle of the current‘s flow from positive to negative is known as classical current. Electrons are negative charge carriers. Considering the current flowing in the gas or solution, we see that there are also positive charge carriers. These are positive ions such as neon, sodium, and copper. Electrons carry negative charge from negative to the positive end. At the same time, positive ions carry a positive charge from the positive to the negative end. In this way, a two-way load flow occurs.
SEE ALSO: What is Alternating (AC) Current?
What is the Unit of the Current?
The electric current unit is the ampere and its symbol is A. There are also books that use the expression Amp briefly. A typical electric bulb powered from the mains requires a current of 1/3 A to light up brightly. Small currents are expressed in milliamps. The symbol of a milliamp is mA and means one-thousandth of an ampere. For example, a flashlight draws a current of about 60mA.
A much smaller current unit is a microampere and its symbol is shown in uA. A microampere is one-thousandth of a milliamp and one-millionth of an ampere. Electronic wall and wristwatches attract only a few microamps. Thus, clock batteries can be used for a long time.
Types of Electric Current
We can briefly distinguish the electric current type as direct current, alternating (variable) current and mixed current;
The voltage at the ends of a battery remains constant until cell energy runs out. Since the voltage is constant, the current flowing in the circuit will also be constant. For this reason, the timed flow graph will be in the form of a horizontal straight line as seen below. This type of flat constant current is called a direct current. Direct current is generally used by shortening it to DC.
The current form obtained from other generators, for example, mains voltages are different from direct current. Such a current is constantly changing direction. Such currents are called alternating currents. Alternating current is generally used by shortening it to AC.
In a circuit, if both direct current and alternating current are effective, this is a mixed current. In the mixed current, electrons move in the same direction, but at a slow speed.