In a series combination of resistors, the voltage (V) across each resistor varies, but the total voltage across the combination remains constant. This is because the resistors are connected one after another, forming a single path for the current to flow through. According to Ohm's Law (V = I * R), the voltage drop across a resistor is directly proportional to its resistance (R) when the current (I) flowing through it is constant. Since the current is the same throughout a series circuit, the voltage drop across each resistor will depend on its individual resistance.
In a parallel combination of resistors, on the other hand, the voltage across each resistor is the same, while the total current flowing into the combination varies. This occurs because each resistor in a parallel circuit has its own separate path for the current to flow through. When resistors are connected in parallel, the voltage across each resistor is determined by the voltage source connected to the circuit, and is independent of the resistance of other resistors in the combination.
To summarize:
- In a series combination, voltage varies across each resistor, but the total voltage across the combination remains constant.
- In a parallel combination, the voltage is the same across each resistor, while the total current flowing into the combination varies.