Worksheet: Light-emitting Diodes
In this worksheet, we will practice identifying the action of LEDs in circuits
The diagram shows a circuit containing several diodes and LEDs. How many of the LEDs in the circuit are lit?
The diagram shows a circuit containing a cell, a resistor, and an LED. The LED does not turn on. Which of the following reasons explains why?
- AAn LED can only be used with alternating current power sources. A cell provides direct current, so the LED will not work.
- BAn LED is a type of diode. Current only flows in one direction through a diode, and in this circuit, the diode is connected in the wrong direction to allow current through it.
- CAn LED cannot be placed in series with a resistor.
- DThe current through the LED is too large. LEDs can only work with small currents.
- EAn LED can only be used in logic circuits.
Which of the following correctly describes an LED?
- AAn LED is a type of diode that emits light.
- BAn LED is a type of resistor; the resistance of an LED decreases as the amount of light incident on it increases.
- CAn LED is a type of resistor; the resistance of an LED decreases as the temperature of the LED increases.
- DAn LED is a type of diode that only allows current through in one direction when the light incident upon it is greater than a certain amount.
- EAn LED is a type of diode that emits sound waves at a specific frequency.
Which of the following circuit symbols represents an LED?