The movement of charged particles within a conducting medium is generally referred to as current. The term “charged particles” in relation to electricity primarily refers to electrons. The conducting material’s atoms have free electrons that can travel from one atom to another. The electrons move in a random manner. Alternating and direct current are the two main forms of current.

In alternating current, the current’s direction is reversed, whereas in direct current, electrons flow in one direction. In batteries, you can find direct current. In a battery, the electron always moves from the negative side to the positive side. Alternating current, on the other hand, can be used in televisions, kitchen appliances, etc.

What is Current?

The current simply refers to the flow of some entity in a specific area. For instance, it can be argued that an air current is flowing if air is blowing in that location. The movement of electrons that represent electric charge, from one location to another is what generates electrical energy in the case of electricity. Electric current is a specific phenomenon. Current play a significant role in daily life. The SI unit of current is Ampere.

The term “current” refers to the movement of electrons. Direct Current (DC) and Alternating Current (AC) are the two major forms of current. While alternating current travels in two directions, direct current only flows in one. Alternating power is provided to our homes and the nearby utilities. Batteries and home electronics both use DC currents. There are several different current types that are employed in daily life. Various current varieties are listed in the section after this.

Various Types of Current

The different types of current are listed below.

• Direct Current (DC)
• Alternating Current (AC)
• Steady Current
• Varying Current
• Instantaneous Current

Direct Current

In general, direct current (DC) travels in a straight line. Direct current is created via battery circuits. because in batteries, the passage of electrical electrons from anode to cathode can only go in a single way. As DC current flows in the same direction, its frequency stays zero. To control the large power supplies that are needed to control various electronic systems, including electric cars, motors, and other devices, direct current is employed to charge the batteries.

Direct Current Symbol

 The following basic ideas and formulas relating to DC circuits and electrical components must be understood.

Ohm’s Law for DC Circuits

Ohm’s Law is fundamental in DC circuits and relates voltage (V), current (I), and resistance (R).

V = I × R

Where

• V is the voltage in volts (V).
• I is the current in amperes (A).
• R is the resistance in ohms (Ω).

Power in a DC Circuit

The power (P) in a DC circuit can be calculated using the formula.

P = V × I

Where

• P is the power in watts (W).
• V is the voltage in volts (V).
• I is the current in amperes (A).

Electrical Energy

Electrical energy (E) consumed or delivered by a DC circuit can be calculated using the formula:

E = P × t

Where

• E is the electrical energy in watt-hours (Wh) or joules (J).
• P is the power in watts (W).
• t is the time in hours (h).

Alternating Current

Alternating current (AC) denotes the flow of the electric charge, which periodically reverses. AC mostly starts from zero then increases to the maximum and again decreases to zero. It reaches the maximum in opposite direction from zero to maximum then again reduces to zero.

Alternate Current Symbol

The particular graph of alternating current is similar to a wave due to its simultaneous growth in both directions It is due to the Alternating current, which is produced by applying various devices which are further known as alternators. However, different methods can be used in the production of AC by using many circuits.

Alternate Current Waveform

Alternating current (AC) circuits use time-varying voltages and currents that change direction on a regular basis. Several key mathematics and concepts are utilized to evaluate and comprehend AC circuits:

Instantaneous Voltage and Current

In an AC circuit, voltage and current change over time. They can be represented as functions of time.

For voltage (V(t)): V(t) = V_m sin (ωt + φ)

For current (I(t)): I(t) = I_m sin (ωt + φ)

Where

• V(t) and I(t) are the instantaneous voltage and current at time t.
• Vm and Im are the peak voltage and current amplitudes.
• ω (omega) is the angular frequency (2πf).
• φ (phi) is the phase angle, which represents the phase relationship between voltage and current.

Root Mean Square (RMS) Values

To describe the effective or equivalent DC value of an AC signal, the RMS value is used.

V_rms = V_m / √2

I_rms = I_m / √2

These values are useful for calculating power in AC circuits.

AC Power

AC power is calculated using the RMS values of voltage and current:

P = V_rms * I_rms * cos(φ)

Where

• P is the real power in watts (W).
• Vrms and Irms are the RMS voltage and current.
• φ is the phase angle between voltage and current, and cos(φ) is the power factor.

Steady Current

In this case, the current’s strength is not affected by time. These currents circulate in an unbroken loop. A straight line will result from the fluctuations if current and time are graphed together.

Varying Current

A current is referred to as changing when its magnitude fluctuates over time. Here, the direction of the stream is constant, but the magnitude varies with respect to time.

Instantaneous Current

It made reference to the value of current at a specific time. It is distinguished by two types. current that charges and discharges. Here, the flow rate changes over time. Small amounts of time, like a millisecond, are taken into account.

Types of Current in Semiconductors

The two types of current in semiconductors are:

• Drift Current
• Diffusion Current

Drift Current

When an external electric field is applied across semiconductor the velocity of the charged particles increases and the particle starts drifting in the resultant direction. This velocity of charged particle drift is called as the drift velocity and the current produced is called the drift current.

Diffusion Current

In doped semiconductor, the movement of charged particles from higher density to lower density is called diffusion current. The diffusion current flows until the particles are distributed uniformly.

Electric Current Applications

Some of the applications of electric current are that it is used to operate electrical devices and used in transports, electronic devices like mobiles, refrigerators etc.

Applications of Direct Current

The below are some applications of direct current.

• DC is used in devices that uses batteries like calculators, toys.
• DC motors use direct current.
• Electronic circuits mostly use direct current.

Applications of Alternating Current

The below are some applications of alternating current.

• AC is used in domestic electronic devices.
• Different motors like induction motor, single phase motors operate on AC.
• Lights like LED bulbs, and other lighting devices use AC.

Difference Between Alternating Current & Direct Current

The difference between alternating current and direct current is given below.