- Define and explain Series and Parallel in your own words
- Use key terms such as voltage accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
This lesson focuses on Series and Parallel: comparing current, voltage and resistance in the two circuit types.
Comparing current, voltage and resistance in the two circuit types.
Key ideas
Series and parallel circuits behave differently
In series there is one path: current is the same everywhere, voltages add, and one break stops everything. In parallel each branch gets the full voltage, currents add, and branches work independently — which is why homes are wired in parallel so one faulty appliance does not kill the lights.
Voltage, current and resistance are linked by V = IR
Voltage drives current through resistance like pressure drives water through a pipe. Doubling the voltage doubles the current through a fixed resistor. Ohmic conductors give a straight-line current–voltage graph through the origin — this is Ohm's law.
Key term — voltage: The energy transferred per unit charge, measured in volts (V) — the 'push' driving the current.
Why does one blown bulb not darken the other bulbs in a house?
House circuits are parallel, so each bulb has its own independent path to the full voltage.
Answer: House circuits are parallel, so each bulb has its own independent path to the full voltage.
- Connecting a voltmeter in series Voltmeters connect in parallel across the component — in series they would block the current.
- Saying current is 'used up' in a circuit Current is the same all round a series loop; it is energy that is transferred to the components.
Practice
Total R = 12 Ω, so I = 12 ÷ 12 = 1 A.
0.5 × 20 = 10 C.
12 ÷ 2 = 6 Ω.
5 × 230 = 1150 W.
Quick check
Which of these best defines "voltage"?
How much energy does a 100 W bulb transfer in 60 s?
- Series and Parallel: comparing current, voltage and resistance in the two circuit types.
- Series and parallel circuits behave differently: In series there is one path: current is the same everywhere, voltages add, and one break stops everything.
- resistance: How much a component opposes current, measured in ohms (Ω).
- Watch out for: connecting a voltmeter in series