27.2:
Resistors In Series
Resistors are one of the most widely used electrical components, used to regulate the current in a circuit.
When the elements are connected in sequence one after the other, it is called a series connection.
In a series connection, if one element in the series breaks, it affects the other elements.
Consider three resistors in a series combination connected to a battery of voltage, "V" and current "I".
The combination of resistors can be treated as equivalent to a single resistor.
Since there is only one path for charges to flow through, the current flow through each resistor is the same. In contrast, the potential drop across each resistor varies depending on the value of the resistor.
The total potential difference across the terminals is the sum of individual potential differences.
The ratio of potential difference and the total current equals the equivalent resistance.
The expression for equivalent resistance can be generalized for the “n” number of resistors connected in the series.
27.2:
Resistors In Series
A resistor is an ohmic device that limits the flow of charge in a circuit. Most circuits have more than one resistor. If several resistors are connected together and connected to a battery, the current supplied by the battery depends on the equivalent resistance of the circuit. The equivalent resistance of a combination of resistors depends on both their individual values and how they are connected. The simplest combination of resistors is the series combination.
In a series circuit, the output current of the first resistor flows into the input of the second resistor; therefore, the current is the same in each resistor. The potential drop across the resistor is equal to the loss of electric potential energy as current travels through it. According to Ohm's law, the potential drop V across a resistor when a current flows through it is calculated using the equation V = IR, where I is the current in amperes and R is the resistance in ohms.
The equivalent resistance of a set of resistors in a series connection is equal to the algebraic sum of the individual resistances. Any number of resistors can be connected in series. If n resistors are connected in series, the equivalent resistance is:
The disadvantage in a series circuit is that if something happens to one component, it affects all the other components. For example, if several lamps are connected in series and one bulb burns out, all the other lamps go dark.
Suggested Reading
- OpenStax. (2019). University Physics Vol. 2. [Web version]. Retrieved from https://openstax.org/details/books/university-physics-volume-2; section 10.2; pages 440–441.