# Series circuit voltage and current relationship

### Series and parallel circuits - Wikipedia

Electronics Tutorial about the Relationship between Voltage Current and Resistance in an Electrical Circuit and their relationship using Ohms Law. Components of an electrical circuit or electronic circuit can be connected in many different ways In a series circuit, the current through each of the components is the same, and the voltage If the four light bulbs are connected in series, there is the same current through all of them, and the voltage drop is V across each. It defines the relationship between the three fundamental electrical quantities: current, voltage, and resistance. When a voltage is applied to a circuit containing .

More Practice Make, solve and check your own problems by using the Equivalent Resistance widget below.

Make yourself a problem with any number of resistors and any values. Solve the problem; then click on the Submit button to check your answer.

### Series and Parallel Circuits

The current in a series circuit is everywhere the same. Charge does NOT pile up and begin to accumulate at any given location such that the current at one location is more than at other locations. Charge does NOT become used up by resistors such that there is less of it at one location compared to another.

The charges can be thought of as marching together through the wires of an electric circuit, everywhere marching at the same rate. Current - the rate at which charge flows - is everywhere the same. It is the same at the first resistor as it is at the last resistor as it is in the battery. These current values are easily calculated if the battery voltage is known and the individual resistance values are known.

### BBC - GCSE Bitesize: Parallel circuits - Higher tier

Using the individual resistor values and the equation above, the equivalent resistance can be calculated. This is to say that the electric potential at the positive terminal is 1. As charge moves through the external circuit, it encounters a loss of 1. This loss in electric potential is referred to as a voltage drop. It occurs as the electrical energy of the charge is transformed to other forms of energy thermal, light, mechanical, etc. If an electric circuit powered by a 1.

There is a voltage drop for each resistor, but the sum of these voltage drops is 1. This concept can be expressed mathematically by the following equation: To illustrate this mathematical principle in action, consider the two circuits shown below in Diagrams A and B.

**Electric Circuits: Basics of the voltage and current laws.**

Suppose that you were to asked to determine the two unknown values of the electric potential difference across the light bulbs in each circuit. To determine their values, you would have to use the equation above. The battery is depicted by its customary schematic symbol and its voltage is listed next to it. Determine the voltage drop for the two light bulbs and then click the Check Answers button to see if you are correct.

Earlier in Lesson 1, the use of an electric potential diagram was discussed. An electric potential diagram is a conceptual tool for representing the electric potential difference between several points on an electric circuit. Consider the circuit diagram below and its corresponding electric potential diagram. The circuit shown in the diagram above is powered by a volt energy source.

There are three resistors in the circuit connected in series, each having its own voltage drop. The negative sign for the electric potential difference simply denotes that there is a loss in electric potential when passing through the resistor. Conventional current is directed through the external circuit from the positive terminal to the negative terminal.

## Series Circuits

Since the schematic symbol for a voltage source uses a long bar to represent the positive terminal, location A in the diagram is at the positive terminal or the high potential terminal. Parallel circuits A parallel circuit is a circuit in which the resistors are arranged with their heads connected together, and their tails connected together.

The current in a parallel circuit breaks up, with some flowing along each parallel branch and re-combining when the branches meet again.

The voltage across each resistor in parallel is the same.

The total resistance of a set of resistors in parallel is found by adding up the reciprocals of the resistance values, and then taking the reciprocal of the total: A parallel circuit is shown in the diagram above. In this case the current supplied by the battery splits up, and the amount going through each resistor depends on the resistance. The voltage across each resistor is 10 V, so: A parallel resistor short-cut If the resistors in parallel are identical, it can be very easy to work out the equivalent resistance.

In this case the equivalent resistance of N identical resistors is the resistance of one resistor divided by N, the number of resistors. So, two ohm resistors in parallel are equivalent to one ohm resistor; five ohm resistors in parallel are equivalent to one ohm resistor, etc.

Here's a way to check your answer. If you have two or more resistors in parallel, look for the one with the smallest resistance. The equivalent resistance will always be between the smallest resistance divided by the number of resistors, and the smallest resistance. You have three resistors in parallel, with values 6 ohms, 9 ohms, and 18 ohms.