Series Circuits

Key Points

• Series Circuit Definition: A single loop where all components are connected one after another.
• Impact of Disconnection: If one component is disconnected or broken, the entire circuit stops working.
• Usage: Due to this vulnerability, very few practical setups use series circuits.

Potential Difference

• Concept: The total potential difference (voltage) of the battery is shared across all components.
• Equation: Total voltage = Voltage across Component 1 + Voltage across Component 2 + ...

Example

• Battery Voltage: 12 volts.
• Two Lamps: If one lamp has a voltage of 8V, the other must have 4V (8 + 4 = 12V).
• Identical Lamps: If both lamps have the same resistance, each gets 6V (12V / 2).

Current

• Flow: Current is the same everywhere in the circuit.
• Measurement: Measured using an ammeter placed anywhere in the series loop.
• Calculation: Current (I) = Total Potential Difference (V) / Total Resistance (R)
• Ammeters generally have negligible resistance and are thus not included in calculations.

Resistance

• Total Resistance: Sum of the individual resistances of each component.
• Symbol: Σ (sum).

Example

• Lamp on Left: 4 ohms.
• Lamp on Right: 2 ohms.
• Total Resistance: 4 + 2 = 6 ohms.
• Current Calculation: 12V / 6Ω = 2A.

Voltage Across Components

• Individual Voltage: Use Ohm's Law (V = IR) to calculate voltage across a specific component.

Example

• Current: 2A (same everywhere in the series circuit).
• Right Lamp Resistance: 2 ohms.
• Voltage Calculation: V = 2A * 2Ω = 4V.
• Remaining Voltage: Total Voltage - Voltage Across One Component (12V - 4V = 8V for the other lamp).*

Voltage Measurement

• Voltmeter: Used to measure voltage across a component; connected in parallel but does not change the series nature of the circuit.
• Voltage Share: Higher resistance components have a higher share of the overall voltage.

Example

• 4 ohm Resistor: Gets 8V.
• 2 ohm Resistor: Gets 4V.
• Reason: More force (voltage) is required to push the charge through areas of higher resistance.

Summary

• Due to Ohm's Law, components with greater resistance will have a higher voltage share.
• Practical use of series circuits is limited due to their sensitivity to disconnection of a single component.