9702 · 10.1
Practical circuits
Welcome to the world of **practical circuits**! This lesson dives into how real-world power sources behave, the fundamental **Kirchhoff's Laws** governing current and voltage, and how we combine components in **series** or **parallel**. You'll also learn the clever trick of **potential dividers** to get just the right voltage where you need it, even with **sensors**. Let's get started! This pilot aligns with **Senpai Corner** AS notes (2025–2027) for topic **10.1**.
Need to know
What you need to know
- E.m.f. (ε) is the total energy supplied per unit charge by a source.
- Potential difference (p.d.) is the energy converted per unit charge between two points in a circuit.
- Internal resistance (r) is the opposition to current flow within the power source itself.
- Terminal p.d. (V) is the voltage across the external circuit: V = ε - Ir.
- The term 'lost volts' refers to the potential difference across the internal resistance (Ir).
Explanation
Practical circuits
- E.m.f. (ε) is the total energy supplied per unit charge by a source.
- Potential difference (p.d.) is the energy converted per unit charge between two points in a circuit.
- Internal resistance (r) is the opposition to current flow within the power source itself.
- Terminal p.d. (V) is the voltage across the external circuit: V = ε - Ir.