Comparison Between Series and Parallel Combinations of Resistors

Feature Series Combination Parallel Combination
Connection Type Resistors are connected end-to-end. Resistors are connected across the same two points.
Current The same current flows through all resistors. The total current is the sum of currents through each resistor.
Voltage The total voltage is the sum of the individual voltage drops. The voltage across each resistor is the same as the source voltage.
Total Resistance Total resistance is the sum of the individual resistances: \( R_s = R_1 + R_2 + R_3 + \dots \) Total resistance is given by: \[ \frac{1}{R_p} = \frac{1}{R_1} + \frac{1}{R_2} + \dots \]
Effect on Total Resistance Total resistance increases as more resistors are added. Total resistance decreases as more resistors are added.
Power Dissipation Power is dissipated across each resistor, proportional to its resistance. Power is dissipated across each resistor, but current is divided among them.
Applications Used when a specific current is required, e.g., for a light bulb circuit. Used in electrical systems where devices need to work independently and get the same voltage.
Advantages Simple to design. Easy to calculate current. Each component gets the same voltage. Independent operation of devices.
Disadvantages If one resistor fails, the entire circuit is broken. If one resistor fails, the total resistance decreases, possibly damaging the circuit.