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AC Circuit Vs DC Circuit – What is the Difference Between these Circuits?

Alternating current (AC) and Direct Current (DC) are the two main types of electricity. Also, these two circuits show the structure of circuit systems.

Inductors, resistors, and capacitors are the primary components of AC circuits. These are all passive electrical components. They have got one common property which is that they all restrict the flow of electric current in a circuit coil. However, they do this in different ways. Our main focus in this article is AC Circuit Vs DC Circuit.

What is an AC Circuit?

Alternating Current Circuit is a type of circuit in which an alternating source powers. This alternating source could be voltage or current. Also, an alternating current or voltage is a type that the amount of current or voltage changes about a distinct mean value.

The voltage and current source has a phase angle in an alternating current. Dividing the resistance by the impedance helps you calculate source voltage and current.  Also, the phase angle has a good effect on the average power the RLC circuit is provided with.

Therefore, one can define an alternating current (AC) as a type of electrical current that alters its value with time and reverses direction. It is different from a direct current (DC), which only travels in one direction.

The sinusoidal voltage and current have been integrated in power businesses and homes for some years of electric power. The AC circuit is the type of circuit that uses alternating source. Also, the AC serves a wide range of domestic and industrial purposes. The direction and magnitude of the voltages and current in an AC circuit has no constant value.

Different Terms Integrated in AC Circuits

Alternating Current vs. Direct Current

Different terms are frequently integrated in AC circuits. These terms include wave form, cycle, alternation, frequency, amplitude, time period, and instantaneous value.

Wave Form

Plotting (I) of an alternating quantity along the Y-axis and the angle or time along the X-axis generated a shape. The shape obtained due to this occurrence is what is referred to as Wave form. (I) here refers to instantaneous value.


One complete cycle occurs when an alternating quantity completes negative and positive values completes or when the values go through 360 degrees electrical.


Amplitude refers to the highest negative or positive value an alternating quantity obtains in a complete cycle. It could be also referred to as maximum value or peak value. Vm and Im represent the amplitude of voltage and current respectively.


Alternation refers to one-half of a cycle. Also, its span is of 180o electrical.


This is simply the number of cycles an alternating quantity makes per second. Frequency is usually measured in hertz (Hz)  or cycle per second (c/s). Also, it is denoted by (f).

Time Period

Time period is the time it takes a voltage or a current to complete one cycle. Time period is usually measured per second and it is denoted by T.

Instantaneous Value

Instantaneous value refers to the value of current or voltage at any instant of time. I or e represents instantaneous value.

AC Circuit Types


AC circuits are available in different types. There are AC circuits having only capacitance (C), only inductance (L), only resistance (R). Some AC circuits combine RC, while some combine LC and some have the combination of the three which is RLC.

RLC AC Circuit

The RLC AC circuit has the combination of resistance, inductance, and capacitance.  It is a type of AC circuit that features a capacitor C, a resistor R, and an inductor L attached in a parallel or series.

The instantaneous voltage over the resistor (R) works in line with the instantaneous current while the instantaneous voltage across the capacitor (C) is behind the instantaneous current. The instantaneous voltage over the inductor (L) drives the instantaneous current.

In an AC Circuit, each voltage can’t sum up. This is because the voltages over the different components are not in phase.

Resistive (R ) AC Circuit

Resistors are electrical components that set, regulate, or impede the movement of current in a definite path. Resistance is the impedance of Resistors. Also, Ohms Ω represents the resistive value of a resistor.

Resistor Inductor (RL) AC Circuit

The RL circuit comprises three different components which are an inductor, a resistor, and an AC generator. The inductor coil generates a back EMF when you activate a circuit switch in an RL AC circuit. Also, it takes the current some time to get to its peak value. The inductive time constant is also known as the time constant.

Applications of AC Circuit

Alternating current  (AC) are widely used in distributing power. One of the main advantages of AC is that you can easily covert it to other voltages. This can be achieved with a simple transformer.

The are lower losses if power is distributed at a high voltage.  For example, a 250 volt supply that carries a  Ω wire resistance  and 14 amps. The power carried is like 1000 watts since watts = volts x amps. Therefore, power loss is calculated as I2 x R = 16 watts.

Therefore, power transmission requires high voltages and these voltages are reduced to a safe level for use within domestic properties. AC is also widely used in supply system. The alternating current is commonly used motors and other items without conversion to direct current.

What is DC Circuit?

DC Circuit

The direct current (DC) circuit is a type of electrical circuit that comprises resistive loads (resistors) and current sources. Also, the DC circuit doesn’t work with time, so, it is independent of time. A circuit is a Direct current circuit if it doesn’t need any past value of its current and voltage.

Since it doesn’t require any past value of its voltage or current, it doesn’t integrate any complex calculation that comprises transient period. Also, a circuit can be referred to as a DC circuit if powered by DC sources like DC power supply or battery.

Direct current is the propagation of electric charge in an unidirectional way. This current is widely integrated  in solar cells and batteries. Also, the DC current was invented by Tomas Edison. This current helped to power a good number of complex electrical systems.

The direct current only flows in just one direction. For instance, a battery provides direct current in a circuit that lights a bulb with a battery.

Applications of DC Circuit

Direct Current circuit is available in applications that have low and extremely low voltage, particularly for solar cells and batteries. Also, the majority of electronic devices need DC power supply and DC voltage. It is important to consider the polarity of DC when using DC devices. Otherwise, you will break it.

It is advisable to connect the appropriate polarity even if your DC devices feature a diode bridge element. DC voltage is widely integrated in the automotive sector. For instance, electric vehicles are making use of DC voltage. These vehicles use batteries.  Also, DC voltage systems are commonly used in diesel engines in heavy duty machines, heavy trucks and machines.

The telecommunication technology isn’t also left out. This technology makes use of DC power supplies. Also, this power supply is useful when there is a disruption during operation as it plays a significant role in maintaining the connection lines for subscribers.

High voltage power transmission integrates DC electricity since the losses by HVDC are cheaper and lower in long distance transmission.

Common Applications of DC Circuits


Non-rechargeable and re-chargeable batteries supply DC. Also, the rechargeable batteries use direct current to recharge themselves.

 Electronic equipment

 Electronic equipment such as computers, televisions, and radios among others integrate direct current to power their circuits. Integrated circuits need direct current to power them. These circuits will get damaged if there is a supply of reverse polarity. Although a good number of these items is powered by Alternating current.

Some electrical equipment

Some pieces of electrical equipment integrate alternating current. However, there are some that integrate direct current.

 Solar panels

 Solar panels generate direct current from the solar panels themselves. These panels generate electricity. When these panels are used with AC mains to supply into the mains for AC supplies, an inverter is needed to enable the conversion of the DC from the solar panels to AC.

AC Circuit vs DC Circuit

There can be a decision based on which current to use in several areas. It is important to know the difference between AC Circuit vs DC Circuit. Also, you should know the form of supply ideal for a particular application.

AC Circuit vs DC Circuit has their benefits and limitations. However, this means you can choose the best option for any particular use or application. Generally, Alternating current (AC) is ideal for use in power distribution. This is the reason the main sockets in offices and homes supply an alternating current. This current powers anything you plug in the main sockets. However, direct current is commonly integrated for printed circuit boards and for many other applications.

Both AC Circuit vs DC Circuit are both widely integrated across electronic and electrical industries, with each providing distinct benefits and ideal for use in different applications. Also, both currents can offer electrical power transfer. However, they do this with slightly different benefits.

Alternating current and direct current are different in terms of power transmission, power generation, and power distribution. However, the main difference between the direct current and alternating is the direction of the flow of electricity. This also serves as the foundation of their diverse characteristics. Furthermore, there is continuous flow of electrons forward or in a particular direction in Direct current.

This is not the case in the AC system. Here, there is exchange in the direction of electrons movement in periodic intervals. Also, this alternating current (AC) makes the voltage value alternate as the value changes along from negative to positive based on the current.

The magnitude of AC varies with time while the magnitude of DC is constant. AC source includes all forms of AC mains and AC generators. DC source include batteries.

Frequently Asked Questions

Why is DC stored in batteries?

You should understand that batteries don’t directly store the energy in them. Batteries are designed to store electrical energy in chemical energy form. In this case, the AC source’s positive terminal connects to the battery’s positive terminal and the AC source’s negative terminal is connects to the battery’s negative terminal. When all these happen, the current begins to flow. However, there is a change in the polarity and there is no supply of the energy. This occurs because the negative half cycle is cancelled out by the negative half cycle. The battery can become damaged if this process persists. Therefore, AC is not stored in batteries.

What are the advantages of AC over DC?

AC has some benefits over DC. One of the advantages of AC over DC is that AC is less costly. Also, it is very easy to generate AC. You can transmit AC across long distances without experiencing much loss of energy. On the other hand DC is very expensive and it experiences energy loss during transmission.  Furthermore, DC is more expensive.

Why is AC voltage preferred over DC voltage?

In most cases, AC voltage is usually preferred to DC voltage. This is because transmission in AC voltages produces less loss of energy. On the other hand, DC voltages experience much loss of energy during transmission. Since AC voltages result in less energy loss, it makes it easy to install when transformers are far away.  Furthermore, AC voltage can step up and step down according to requirement. This is an added advantage.


Both direct current (DC) and alternating current (AC) are both widely integrated across electronic and electrical industries, with each providing distinct benefits and ideal for use in different applications. Also, both currents can offer electrical power transfer. However, they do this with slightly different benefits.

Alternating current and direct current are different in terms of power transmission, power generation, and power distribution. However, the main difference between the direct current and alternating is the direction of the flow of electricity.




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