In wheatstones bridge how a loop is formed ,elaborate with an example

Wheatstone bridge is used to measure the unknown resistance connected in a circuit. It consists of four resistors of which two resistors are known resistors, one variable resistor and one unknown resistor. It also consists of a galvanometer. It consists of two series-parallel arrangements of resistors.

Consider the diagram of Wheatstone bridge given below. It consists of four arms PQ, QR, RS and PS which has fixed and variable resistors. Resistors resists the flow of electric current. Its measure is called Resistance. Here R1 and R2 are the fixed resistors and R3 is the variable resistor and Rx is the unknown resistor. The resistor which restricts and also can control the flow of electric current is called Variable Resistor. It can either increase or decrease the resistance value and thus control the flow of current.

Wheatstone Bridge

The arms PQ and QR are known as Ratio Arms. We can see that a galvanometer is connected between the terminals Q and S. Q and S is called the galvanometer arm. Also the battery is connected to the other two terminals P and R. P and R is called the Battery Arm. By adjusting the value of variable resistor we need to make the deflection in galvanometer as null.