Topic 3: LED Display Device

Which component is essential for limiting the current through an LED?

• Diode

• Transistor

• Resistor

• Capacitor

What is the disadvantage of LED?

• Small area of illumination

• Expensive

• Low operating voltage

• Low power dissipation

What type of seven-segment display requires a common ground connection for all the LED segments?

• Common anode

• Common cathode

• Bipolar display

• Multiplexed display

How many individual LED segments are there in a seven-segment display?

• 5

• 6

• 7

• 8

To operate a seven-segment display safely, what value of resistor is typically connected in series with each segment to limit the current?

• 33 ohms

• 330 ohms

• 33 kohm

• 330 kohm

If segments c, d, e, f, and g are lit on a seven-segment display, what digit will be displayed?

• 2

• 3

• 5

• 6

Which combination of segments forms the digit "5" on a seven-segment display?

• c, b, e, f, g

• a, b, d, e, g

• a, b, d, e, g

• a, c, d, f, g

In an LED, light is emitted when the diodes are

• forward biased.

• reverse biased.

• disconnected.

• connected together.

A 3V supply powers a seven-segment LED display, with the digit "3" being displayed. If each of the segments draws 10 mA, what is the total power drawn from the supply?

• 50 mW

• 100 mW

• 150 mW

• 200mW

Which of the following switches should be closed for the number '4' to appear?

• 2, 3, 4, 5

• 2, 3, 6, 7

• 3, 4, 5, 6

• 3, 4, 6, 7