Voltage in Parallel Circuits


What is meant by the term “parallel circuits”?

Parallel circuits are highly common and will certainly be the first type of circuit. Most loads in electricity grids are linked together in parallel.

parallel 1

Voltage in Parallel Circuit

Each load resistor in a parallel circuit function as a separate branch circuit; as a result, the entire supply voltage is seen by each branch.

In a parallel circuit, the total voltage is equal to the voltage across each individual conductor.

The parallel circuit principle to understand is that the voltage across each parallel component is equal.

In a parallel circuit, there are only two sets of electrically common points, and the voltage measured between both sets must always be the same.

Nodes 1, 2, 3, and 4 etc., in the circuit  are the same electrical node. Similarly, nodes 5, 6, 7, and 8 constitute a same electrical node.

The voltage across R1 is therefore equal to the voltage across the R2, which is equal to the voltage across the R3, which is equal to the voltage across the battery.

voltage 2

As an expression of this connection:

VT = V1 = V2 = V3

Consider a voltage source & a resistor in a closed circuit. The current in this circuit will flow through the single available pathway.

Then  add two more resistors in parallel with the first resistor in the same circuit.

As a result, the current must travel multiple paths rather than a single path to reach the low potential terminal.

As the number of branches increases, the overall resistance decreases, and it is apparent that the current in the circuit also increases.

As a result, the total current will be the sum of the currents flowing through the three resistors.

In the parallel circuit that there are only two sets of electrically common points.  

voltage 3

Voltage should be constant when measured across common points over time.

ITotalrepresents the total current in this parallel circuit. The formula for determining  is as follows.

ITotal = I1 + I2 + I3

The formula below describes the total (or) effective resistance of this given parallel circuit.


As a result, adding additional branches to a particular parallel circuit increases the total current and overloads the circuit.

In a parallel circuit, how to find the applied voltage?

The voltage applied to an element is referred to as the applied voltage. The total voltage in a parallel circuit is the applied voltage.

It is also equivalent to voltage drops in individual circuit branches. The applied voltage and branch voltages will not be equal if the parallel circuit is not the only portion of the network.

Voltage Drops in Parallel Circuit

The sum of the voltage drops in the external circuit equals the voltage gain as a charge flows through the internal circuit.

A charge does not pass through every resistor in a parallel circuit; rather, it flows through a single resistor.

As a result, the total voltage drop across that resistor must equal the battery voltage.

The voltage drop across the resistor that the charge chooses to flow through must equal the voltage of the battery, regardless of whether it flows through resistor R1, resistor R2, or resistor R3.

This principle would be expressed in equation form as

Vbattery = V1 = V2 = V3 = …

If three resistors are connected in parallel and powered by a 12-volt battery, the voltage drop across each resistor is 12 volts.

A charge flowing through the circuit would only come into contact with one of these three resistors, resulting in a single voltage drop of 12 volts.

What does Kirchhoff’s Voltage Law (KVL) State?

Kirchhoff’s Voltage Law

In any closed loop within a circuit, the algebraic sum of voltage applied is equal the sum of all voltagedrop in the element in a closed loop.

voltage 4
voltage 5

Find missing values using Ohm’s Law

Ohm’s Law states that

V = IR

If know two of these values, apply this formula to find the third.

Ensure sure each value refers to the same circuit part. Users can use Ohm’s Law to analyse the entire circuit

V = ITRT (or) single branch V = I1R1

Parallel Voltage Application

Voltages in parallel have the following applications:

  • Domestic appliances.
  • Circuits for lighting.
  • Ring of power.
  • Parallel capacitors.