T6.1 Series combination of Resistors:

When the resistances are connected in series, the same current flow through each of the resistance.

Consider three resistors $R_1$, $R_2$ and $R_3$ connected in series. The same current flows through each resistor, but voltage (potential difference) across the resistors is different. 

The total voltage, $V$ flowing in the circuit is the sum of the Voltage in different resistors. i.e.

$V = V_1 + V_2 + V_3$ .......... (i)

Let $I$ be the current flowing through each resistor and $V_1$, $V_2$, $V_3$ be the potential difference across $R_1$, $R_2$ and $R_3$ respectively.

From the Ohm's law:

$V_1 = IR_1$ .......... (ii) 

$V_2 = IR_2$ .......... (iii) 

$V_3 = IR_3$ .......... (iv)

From the equation (i), (ii), (iii) and (iv)

$V = I\,R_1 + I\,R_2 + I\,R_3$ 

$V = I(R_1 + R_2 + R_3)$ 

$\frac{V}{I} = R_s = R_1 + R_2 + R_3$ .......... (v)

Where, $R_s = R_1 + R_2 +R_3$ be the equivalence resistance of the series combination.

The equivalent resistance of the series combination is equal to the sum of the resistance of individual resistors. 

So the equivalent resistance increase in the series combination (Principle of PHYSICS). 

Return to Main Menu