How does series circuit work

In this circuit all the components are connected in the same loop. The most common example of Series-Circuit is fancy lights or string lights. The path for flow of electrons electricity is called a Circuit. The intent of any electrical circuit is to supply electricity for an appliance or any electrical device. These devices are called loads. Before the load operates, electricity must have a definite path from the source to the load and back to the source. The figure below shows a typical Series-Circuit where the Resistors R1, R2, R3 are connected subsequently with the end of one resistor connected to the other end of the next resistor to form a loop.

The current flows from negative terminal of the battery through the resistors and hence the current is same across all the components in a Series Circuit.

The total resistance in a Series Circuit is equal to sum of the individual resistances. The voltage is different across different resistors and the sum of voltage drop across each component resistor is equal to the applied voltage. A break in the Series-Circuit will stop the current flow across the circuit. Each charge passing through the loop of the external circuit will pass through each resistor in consecutive fashion.

A short comparison and contrast between series and parallel circuits was made in the previous section of Lesson 4. In that section, it was emphasized that the act of adding more resistors to a series circuit results in the rather expected result of having more overall resistance. Since there is only one pathway through the circuit, every charge encounters the resistance of every device; so adding more devices results in more overall resistance. This increased resistance serves to reduce the rate at which charge flows also known as the current.

Charge flows together through the external circuit at a rate that is everywhere the same. The current is no greater at one location as it is at another location. The actual amount of current varies inversely with the amount of overall resistance. There is a clear relationship between the resistance of the individual resistors and the overall resistance of the collection of resistors. This is the concept of equivalent resistance. The equivalent resistance of a circuit is the amount of resistance that a single resistor would need in order to equal the overall effect of the collection of resistors that are present in the circuit.

For series circuits, the mathematical formula for computing the equivalent resistance R eq is. 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. Mathematically, one might write. These current values are easily calculated if the battery voltage is known and the individual resistance values are known.

Using the individual resistor values and the equation above, the equivalent resistance can be calculated. As discussed in Lesson 1 , the electrochemical cell of a circuit supplies energy to the charge to move it through the cell and to establish an electric potential difference across the two ends of the external circuit.

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. 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. 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. Location A is at 12 volts of electric potential and location H the negative terminal is at 0 volts.

In passing through the battery, the charge gains 12 volts of electric potential. And in passing through the external circuit, the charge loses 12 volts of electric potential as depicted by the electric potential diagram shown to the right of the schematic diagram. This 12 volts of electric potential is lost in three steps with each step corresponding to the flow through a resistor.

In passing through the connecting wires between resistors, there is little loss in electric potential due to the fact that a wire offers relatively little resistance to the flow of charge. Since locations A and B are separated by a wire, they are at virtually the same electric potential of 12 V.

When a charge passes through its first resistor, it loses 3 V of electric potential and drops down to 9 V at location C. Since location D is separated from location C by a mere wire, it is at virtually the same 9 V electric potential as C. An ammeter will measure the same current wherever it is placed in the circuit:. This is when:. If the resistance of any component in a series circuit changes, this will change the value of the current in the circuit.

The current will transfer energy from the power supply to the components in the circuit.