LED Circuit Functionality and Components

LED Circuit Functionality and Components

Assessment

Interactive Video

Physics, Science, Chemistry

9th - 12th Grade

Practice Problem

Hard

Created by

Liam Anderson

FREE Resource

This video tutorial explains the construction and operation of a simple LED flasher circuit using an NPN transistor, resistor, capacitor, battery, and LED. It delves into the concept of negative resistance, detailing how it affects the circuit's operation. The tutorial also covers the specifications of the components used, the circuit's operation, and how to adjust the LED's flash rate using resistance and capacitance values. Additionally, it demonstrates how to enhance the circuit by adding more LEDs in parallel.

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10 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What are the basic components required for the LED flasher circuit?

NPN transistor, resistor, capacitor, battery, LED

PNP transistor, inductor, diode, battery, LED

PNP transistor, resistor, capacitor, battery, LED

NPN transistor, inductor, capacitor, battery, LED

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How does negative resistance differ from positive resistance?

In negative resistance, voltage and current decrease together.

In negative resistance, voltage increases as current decreases.

In negative resistance, voltage decreases as current decreases.

In negative resistance, voltage and current increase together.

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the breakdown voltage of the NPN transistor used in the circuit?

12.0 volts

9.0 volts

7.3 volts

5.0 volts

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

Why is a 12-volt battery recommended for this circuit?

To increase the lifespan of the components

To ensure the LED flashes at a higher frequency

To provide enough voltage for the circuit to start

To reduce the current flowing through the circuit

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What happens when the voltage across the capacitor reaches the breakdown voltage of the transistor?

The LED turns off

The capacitor discharges through the transistor

The transistor stops conducting

The capacitor stops charging

6.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the minimum voltage required to light up the LED in this circuit?

9.3 volts

12.0 volts

7.3 volts

5.0 volts

7.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How can the flash rate of the LED be increased?

By increasing the capacitance

By using a lower voltage battery

By decreasing the resistance

By increasing the resistance

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