Resistors & Diodes
Science: KS3, topic 3.4.2
Resistors and Diodes
Resistors and diodes are some of the more useful (and complex) circuit parts.
Resistors
- Resistors
- Resistors can limit the current flow at a fixed Amperage.
- Variable resistors limit the current flow.
- Variable resistors can be adjusted.
Thermistors
- A thermistor restricts current flow depending on the temperature.
- In a fire alarm, the temperature of a room can increase.
- The thermistor then allows more current through to sound the alarm.
Light-dependent resistors
- A light-dependent resistor is also called an LDR.
- An LDR changes the amount of current flowing through a circuit.
- The current changes based on light levels.
Diodes
- A diode only allows current through in one direction.
- A light-emitting diode (LED) lights up as a current flows through it.
Test yourself on Resistors & Diodes
What is a resistor?
What does LED stand for?
Which are true of variable resistors?
An LED is connected into a circuit the wrong way round. What happens when the circuit is switched on?
A circuit needs a component that always limits the current to the same fixed amount. Which component fits this?