Summary
Potential dividers are used in circuits to divide the voltage among components, allowing for control over the output voltage. They are crucial in applications where voltage needs to be adjusted based on external conditions.
- Variable Resistors — components that allow for the adjustment of resistance and output voltage in a circuit.
Example: Potentiometers and sensory resistors like LDRs and thermistors. - Light Dependent Resistors (LDRs) — resistors whose resistance decreases with increasing light intensity.
Example: Used in streetlights to turn on lights when it gets dark. - Thermistors — resistors whose resistance decreases with increasing temperature.
Example: Used in fire alarms to detect temperature changes. - Potentiometer — a variable resistor that provides a continuously adjustable output voltage.
Example: Used for precise voltage control in circuits. - Galvanometer — a device used to detect and measure small electric currents.
Example: Used with potentiometers to measure electromotive force (EMF).
Exam Tips
Key Definitions to Remember
- Potential divider: A circuit used to divide voltage among components.
- Variable resistor: A component that allows for the adjustment of resistance and voltage.
- Potentiometer: A variable resistor for precise voltage control.
- Galvanometer: A device for detecting and measuring small currents.
Common Confusions
- Confusing the function of LDRs and thermistors.
- Misunderstanding how potentiometers adjust voltage.
Typical Exam Questions
- What is a potential divider? A circuit that divides voltage among components.
- How does a potentiometer work? By adjusting the slider to change resistance and output voltage.
- What happens to the resistance of an LDR when light intensity increases? The resistance decreases.
What Examiners Usually Test
- Understanding of how potential dividers work.
- Ability to explain the function of variable resistors.
- Knowledge of how to use a galvanometer with a potentiometer.