### Series And Parallel Combination Of Resistances

**Concepts from the chapter Series and Parallel Combination of Resistances:**

**Ohm’s Law**:

- States that the current flowing through a conductor is directly proportional to the potential difference applied across it, provided the temperature remains constant.

**Different Types of Circuits**:

**Series Circuit:**In a series circuit, the components are connected in a single pathway so that the current passes through each component one after another.**Parallel Circuit:**In a parallel circuit, the components are connected in multiple pathways, allowing the current to flow through any path available.**Complex Circuit:**A circuit that contains combinations of series and parallel connections is known as a complex circuit.

**Resistance in Series**:

- When resistors are connected in series, the total resistance of the circuit increases. The total resistance is the sum of the individual resistances.
- The current through each resistor remains the same in a series circuit, but the voltage across each resistor can be different.

**Resistance in Parallel**:

- When resistors are connected in parallel, the total resistance of the circuit decreases. The total resistance is calculated using the reciprocal formula: 1/Rtotal = 1/R1 + 1/R2 + 1/R3 +…
- The voltage across each resistor in a parallel circuit is the same, but the current through each resistor can be different.

**Effective Resistance**:

- The effective resistance (or equivalent resistance) of a circuit is the single resistance that, when used in place of the original circuit, would result in the same current and voltage values at every point in the circuit.

**Kirchoff’s Laws**:

**Kirchoff’s Current Law (KCL):**The total current entering a junction (node) must equal the total current leaving the same junction.**Kirchoff’s Voltage Law (KVL):**The algebraic sum of the voltages around any closed loop in a circuit must equal zero.

**Wheatstone Bridge**:

- A Wheatstone bridge is an electrical circuit used to measure an unknown resistance by balancing two legs of the bridge against each other. When the bridge is balanced, the potential difference across the galvanometer is zero, and the unknown resistance can be calculated using simple ratios of the known resistances.

**Meter Bridge & Potentiometer**:

**Meter bridge:**a measuring device used to determine an unknown resistance by comparing it to a known resistance.**Potentiometer:**a device used to measure an unknown voltage or potential difference by comparing it to a known voltage.

**Combination of Resistors**:

- Resistors can be connected in different combinations, including series, parallel, and complex arrangements, to achieve specific resistance values and control the flow of current in a circuit.