Difference between Current and Voltage with Comparison Chart

The main difference between current and voltage is that current is the rate of flow of electrons in a specific direction, while voltage is an electric pressure that forces electrons or charge carriers through a conductor.

This article describes the key differences between current and voltage. First, let’s understand what the current and voltage are.

What is Current?

The electrons or charge carriers start drifting when voltage is applied across the conductor. The drift velocity of electrons depends on the conductor’s voltage and resistance. The flow of electrons causes current to flow. Thus, the current is defined as the rate of flow of electrons through the conductor.

The flow of electric current may be constant or time-varying, depending on the voltage source type. The current flow is constant if DC voltage is applied across the conductor. In the case of AC voltage, the current flow varies.

The current is typically represented by the letter I or i, with “I” indicating a constant current and “i” indicating a time-varying current.

We can define current as the flow rate of electric charge. Mathematically, the current can be expressed as;

In derivative form, current can be expressed as;

You can find the unit of the current from the above formulas.

Thus, the ampere is the SI unit of the current.

The ampere meter or ammeter is used to measure the current. The ammeter has very low resistance and is connected in the series to the circuit.

What is Voltage?

Voltage is the driving force behind the flow of current. The voltage creates an electric pressure that pushes the electric charges through the conductor, and it causes the flow of current in an electric circuit.

The amount of current flowing in the circuit depends on the magnitude of the potential difference or voltage. Therefore, the higher the voltage, the higher the current in the circuit.

We use the letter V or v to denote voltage. “V” represents a constant voltage, while “v” represents a time-varying voltage.

The electrical force that establishes current between two points is termed voltage.

We can use the following mathematical formula to express the voltage or potential difference.

From the above formula, you can find the unit of voltage.

Volt is the SI unit of the voltage.

The voltmeter is used to measure the potential difference or voltage across two points in an electric circuit. It is connected across the circuit element whose potential is to be measured.

Now, we can list the key differences between the current and voltage.

Difference between Current and Voltage

The key differences between current and voltage are tabulated.

Key	Current	Voltage
Definition	The flow of electric charge through a conductor is called current.	The potential difference between two points in an electric field is called voltage.
Symbol	Current is denoted by the letter “I” or “i”. “I” represents a constant current and “i” represents a varying current.	Voltage is represented by “V” for constant voltage and “v” for varying voltage.
Formula	The formula for current is I = Q/t, where I represents current, Q represents charge, and t represents time.	The formula for voltage is V = W/Q, where V represents voltage, W represents work done, and Q represents charge.
SI Unit	The SI unit of current is Ampere (A). 1 Ampere = 1 Coulomb/Second	The SI unit of voltage is Volt (V). 1 Volt =1 Joule / Coulomb =
Types	There are two types of current – direct current and alternating current.	There are two types of voltage – direct voltage and alternating voltage.
Inter-relation- Cause & Effect	The voltage pushes electric charges and causes current to flow through a circuit.	Voltage is the driving force behind the current flow.
Measuring Instrument	An ammeter is used to measure current.	A voltmeter is used to measure voltage.
Field Created	The current generates electric and magnetic fields.	Voltage generates only an electric field
Loss	The loss of voltage is caused by impedance.	The loss of current occurs because of the passive elements.
In Series Connection	The current remains the same in the series-connected circuit elements.	The voltage varies across each circuit element according to the resistance or impedance of the circuit element.
In Parallel Connection	Current varies and is distributed according to the impedance of the circuit’s element in a parallel connection	The current remains the same in the series-connected circuit elements.

Final Words

In this article, you have learned –

• What is current? – The rate of flow of charge carriers through a conductor is electric current. Its SI unit is Ampere.
• What is voltage?- The work done to move a unit charge from one place to another in an electric field is called voltage. Its SI unit is a volt.
• An ammeter is used to measure current, and a voltmeter is used to measure voltage.
• Both current and voltage are crucial electrical quantities, and understanding these terms is a must to analyze the circuit.
• The voltage causes the flow of current. If there is no voltage, there would be no current.