Four 12 Ω resistors are connected together. What is the least resistance that can be attained with these resistors by connecting them in various ways?
Answers
Answer:
When resistors are connected in parallel, the supply current is equal to the sum of the currents through each resistor. In other words, the currents in the branches of a parallel circuit add up to the supply current.
Also, they have the same potential difference across them. In other words, any components in parallel have the same potential difference across them. And, the total resistance will always be lesser than the least resistance in the circuit.
The total resistance is calculated as
R
T
1
=
R
1
1
+
R
2
1
+
R
3
1
.Thatis,R=R
T
−1
.
In this case, the given resistance are of 1/5 ohms each. Therefore, the minimum resistance that can be obtained from the parallel connection of these five resistors is given as follows.
R
T
1
=
1
5
+
1
5
+
1
5
+
1
5
+
1
5
=
1
25
.Therefore,R=
25
1
.
Hence, the minimum resistance which can be made using five resistors each of 1/5 ohms is 1/25 ohms.