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As the name suggests, direct current is the flow of current in one direction consistently. It is used in batteries, plugs into the wall with an AC adapter or uses a USB cable. Edison developed it. During the early times, direct current was the dominant form in the US.

One cannot convert direct current into higher or lower voltages easily. The change in voltage is difficult as it moves in one direction only. 

Direct current is more stable as compared to alternating current. This aspect has persuaded companies to find ways of using high voltage direct current to transmit electricity over long distances without losing much energy.  

We can convert direct current into alternating current by using an inverter. A rectifier can convert an alternating current into a direct current.  

Properties of Direct Current 

  • The current does not change its polarity. 
  • The flow of electrons in DC is in one direction, from high electron density to low electron density. 
  • The charge flows from the negative to the positive terminal in a battery.
  • It is much more expensive than alternating current.
  • It is generally low voltage, but experts are trying to use high voltage direct current.  

Direct Current Uses

  • DC is useful for many household purposes.
  • Electronic devices such as computers use direct current.
  • Anything that works on a battery or a cell uses direct current. 
  • When a resistor limits DC, it allows light-emitting diodes (LEDs) to produce light. 
  • It allows transistors to amplify AC signals. 
  • It has applications in portable solar systems and other off-grid devices. 
  • They are also used in sensors, as it produces current that allows us to monitor and comprehend the physical conditions of the surrounding environment. 

The Peak Value of Direct Current

Peak value, also called amplitude or crest value, refers to the highest possible value obtained during one cycle. The direct current has a fixed amplitude and direction. It maintains the same value for all times unless we physically reverse it.   

The Waveform of DC

Waveforms help represent the flow of AC over a graph. Faraday’s law of electromagnetic induction explains the science behind waveform generation clearly. 

A pure sine wave represents DC. The voltage remains constant with respect to time.  

Conversion of AC into DC

We can convert alternating current into direct current in the following ways:

  • Batteries allow chemical reactions. Chemical reactions produce chemical energy, which then converts into electrical energy. 
  • We can convert the alternating current into a direct current using a rectifier. Rectifiers are part of electronic circuits, mobile chargers, etc. 

Conversion of DC into AC

We can convert a direct current into an alternating current using an inverter. An automated switch or mechanism changes the direction of direct current back and forth in an inverter, converting it into alternating current.  

Distinction between Direct Current and Alternating Current

Alternating Current

Direct Current

In AC, the current changes direction periodically.

In DC, the current follows one direction only. 

The voltage in AC circuits regularly reverses due to changes in the current direction. 

The voltage in DC circuits never changes. 

AC is useful for transmitting power over long distances without losing energy. 

We cannot use DC for long distances. 

The frequency of AC changes according to the country but maintains an average of 50-60 Hz.

It has zero frequency. 

It is easier to generate and less expensive.

It is more expensive and difficult to generate than AC. 

We cannot store AC in batteries. 

We can store AC on batteries or in a cell.

It has four types of waveforms: Sinusoidal, Triangular, Square and Sawtooth. 

It has two types of waveforms: Pure and Pulsating.

Conclusion

Direct current is the type of current in which direction does not change at regular intervals. Alternating current is preferred over direct current as it can transfer energy over long distances without losing energy. It is the most commonly used current for electronic devices. 

We can store DC in batteries. We can convert DC into alternating current using an inverter and vice versa using a rectifier.