Difference between Voltage, Current and Resistance

Electricity is an integral component of today’s world. Every electronic device runs on electricity; however, the mode of electrical supply can be different. 

Electricity comes with three crucial factors—voltage, current, and resistance. Today, we will discuss how voltage, current, and resistance work together and understand the transmission mechanisms.

What is Voltage? 

Voltage refers to the potential energy each electron or charge holds in the circuit due to its position. It gives us the measurement of difference between the potential energy across two points and is often considered as the energy per unit.

The calculation unit is volt represented as “V.» 

What is Current?

Current is the measure of the electron flow from positive to negative electrodes or terminals. It tells us the rate at which electrons are flowing through the circuit per minute. Current is quantified in amperes (A).

There are two crucial types of currents.

• AC or alternating current flows in an alternate direction and changes direction every millisecond or less. It is ideal for home appliances and other tools.
• DC or direct current has the same direction and is often helpful for batteries. Solar panels produce DC current. 

What is Resistance?

Resistance means the obstruction to the current flow. It tells us the possibility of the current passage through the circuit. 

The unit to calculate the resistance is ohm. The symbol is “Ω.”

Key Differences between Voltage, Current, and Resistance

There is an ample range of differences between three terminologies. But before we explore, let’s understand Ohm’s law. As per the law:

Voltage = Current x Resistance 

As per the formula, voltage is directly proportional to the current. It means the higher the current is, the higher the voltage will be, and vice versa.

Let’s understand how the voltage, current, and resistance differ from each other.

Measuring Instrument

Measuring instruments differ from voltage to current. Also, you have to understand their connection with the circuit.

For example, a voltmeter measures the voltage, but you should connect it in parallel in the circuit. An ammeter calculates the current in a circuit but requires a series combination. While an ohmmeter calculates resistance, provided there is no current flowing through your circuit.

Function in Circuit

Current means the movement of electrons from one negative terminal to another positive terminal or vice versa. While the voltage is the pushing force that ensures the current flow through the electrodes.

On the other hand, resistance is the opposing force of current. It doesn’t let the electrons pass between the electrodes.

Dependency

Voltage is often independent of the current or resistance. The source of batteries determines if. Current depends on the voltage and resistance. The resistance is constant and remains the same whether you change the voltage or current.

Behavior in a Series Circuit

Voltage gets divided by the number of components in the series circuit. For example, add the total voltage of components and divide it by the number of components. Current remains the same throughout the components. At the same time, the resistance adds to all the elements.

Behavior in a Parallel Circuit

In a parallel circuit, voltage remains the same while current gets divided by the total number of components as above. However, resistance gets divided for each element. 

For example, 1/R is the calculation formula for resistance for each component.

Real-World Analogy

Let’s measure and understand each component in real-world applications.

Voltage = Water Pressure. The high voltage means high pressure to push the current through the circuit.

Current = Flow Rate of Water. It means the total current flowing through the circuit.

Resistance = Pipe Size or Blockage. A narrow or blocked pipe doesn’t let the current pass through it.

Cause/Effect Relationship

Voltage is the cause that causes the pressure to push the current. At the same time, current is the effect of this push. On the other hand, resistance is the control system that blocks or controls the current.

Real-World Examples and Applications

Many applications in our daily lives have current and voltage through the circuits. Let’s take a look at them.

Phone Chargers

Quick and straightforward examples of voltage are the phone charges. Most phone chargers support 5V or higher voltages. However, fast chargers from Xiaomi can charge at 9V or more. Similarly, current flows at a value of 2A or 3A. 

There is no measure of the resistance, as the phone’s internal circuitry manages the resistance.

Home Lighting Systems

Home lighting systems have the same voltage across all the home components. There is 110V to 240V voltage across the whole world in the residential sectors. Current might change depending on the power of the lighting systems. Filaments in the home lighting systems control the resistance to let the current flow.

Electric Vehicles

Electric vehicles have higher voltage levels reaching 800V. However, a higher current value is required to manage such a voltage. The internal system also subtracts the resistance for a seamless current flow. 

FAQs

1. Can you have voltage without current in a circuit?

Yes. Voltage can exist independently of the current if the circuit has infinite resistance or is open. Similarly, batteries retain the voltage without having the current flowing through them.

2. What is the impact of resistance on the current?

A high resistance causes the obstruction in the electronic flow and decreased current. So, current is high in low resistance circuits while low in high resistance circuits.

3. Why does a parallel circuit behave differently from a series circuit?

Parallel and series circuits present a different infrastructure and view of the current and voltages. For example, a parallel circuit has the same voltage across all components. On the other hand, a series circuit has a different voltage across the same components.