# Ch 9: Electricity in Engineering

### About This Chapter

## Electricity in Engineering - Chapter Summary

This collection of engineering lessons provides an overview of electricity's presence and application in engineering. Inside the chapter, you'll find short and informative lessons that illustrate the characteristics of diodes, transistors, voltage, currents and more. Each lesson comes with a convenient self-assessment quiz to help you check your understanding of the material and retain the information you've learned. Your progress through the chapter is tracked on your course Dashboard and you can study these lessons at any time that fits your schedule. Studying these lessons will enable you to:

- Recognize PNP and NPN transistor equations
- Understand the purposes, characteristics and applications of different types of diodes, including Zener, Schottky, laser, TVS, flyback, tunnel and pin diodes
- Define direct current and integrated circuits
- Differentiate between NPN and PNP transistors
- Recognize point of common coupling examples
- Explain the zero voltage switching technique
- Calculate a voltage drop
- Summarize several voltage concepts, including Kirchoff's voltage law, voltage multiplier and divider circuits, amplifier voltage gain and threshold voltage
- Know the difference between voltage and current

### 1. PNP Transistor: Definition & Equations

In this lesson, we learn about PNP transistors - how they function and why they so useful in modern electronics. We will also explore their unique characteristics by deriving mathematical equations.

### 2. What is a Diode? - Definition & Types

In this lesson, we explore the fundamental operation of a diode. We also look are some the various types of diodes, such as the zener diode, the Schottky diode, the light emitting diode, and the laser diode.

### 3. What is a Zener Diode? - Definition & Characteristics

In this lesson we define the zener diode and describe its characteristics. Also, we describe how the zener diode is used as a voltage regulator, a clipping circuit and as a voltage reference.

### 4. What is a Schottky Diode? - Characteristics & Applications

In this lesson we look at the Schottky diode and compare it to the P-N junction diode. We explore why the unique features of the Schottky diode lead to high frequency and power applications.

### 5. What is a Flyback Diode? - Purpose & Calculations

In this lesson we explore the flyback diode and how it protects circuit components when they are temporarily exposed to high voltages caused by changing magnetic fields. This lesson also shows the calculation for diode selection.

### 6. Tunnel Diode: Characteristics & Applications

In this lesson, we describe the characteristics of the tunnel diode. This device finds use at high frequencies. Applications explored are the relaxation oscillator and the harmonic oscillator.

### 7. PIN Diode: Characteristics & Applications

In this lesson, we explore the characteristics of the diode called a PIN diode. In addition to explaining how this diode differs from the more common PN diode, several application examples are presented.

### 8. What is Direct Current?

Current is the flow of electric charge and exists in two forms: direct current and alternating current. In this lesson, you will learn what direct current is and what it is used for.

### 9. What is an Integrated Circuit (IC)?

In this lesson, we will learn about integrated circuits (ICs) and explore their origin, types, and benefits. We will also look at different ways that they are packaged.

### 10. NPN vs. PNP Transistors

In this lesson, we will learn about the physics behind transistors and why they are important as semiconductor devices. We will then compare the characteristics of transistors of the npn and pnp types.

### 11. NPN Transistor: Definition & Equations

In this lesson, we learn about NPN transistors. How do they function and why are they so useful in modern electronics? We'll also explore their unique characteristics by deriving mathematical equations.

### 12. Voltage Drop: Definition & Calculation

Voltage drop specifies the amount of electric power produced or consumed when electric current flows through the voltage drop. Voltage drops can be measured in a circuit with an appropriate instrument, but also can be calculated in advance using appropriate equations.

### 13. Kirchoff's Voltage Law: Definition & Examples

Kirchoff's Voltage Law states that the sum of all voltage changes around a closed path in a circuit is zero. The law is a consequence of energy conservation, and applying the law allows engineers to write some of the equations required for analysis of electric circuits.

### 14. What is Voltage? - Definition & Units

This lesson will describe voltage and its unit, the volt, with an emphasis on the relationship between voltage and the energy associated with electric charge.

### 15. Voltage Divider Circuit: Rule, Bias & Formula

In this lesson, you will learn that a voltage divider is a set of series-connected resistors with an input voltage applied to the entire string. Each resistor develops an output voltage across its terminals that is a fraction of the input voltage. These fractions depend only on the resistance values.

### 16. Amplifier Voltage Gain: Calculation & Formula

In this lesson we describe a voltage amplifier and one of the common specifications for voltage amplifiers. In particular, examples will use a formula for calculating the voltage gain.

### 17. Difference Between Voltage and Current

In electric circuits, current is the flow of charge through any given point, while voltage expresses the energy the charge gains or loses as it moves from point to point and arises from the existence of Coulomb forces everywhere in the circuit. Essentially, voltage is the cause, and current is the effect.

### 18. Power Supply: Definition & Types

In this lesson, we define what a power supply is and what the different types of power sources are. We also explore examples of mechanical and chemical power supplies.

### 19. What is a Light Emitting Diode (LED)? - Definition & Applications

In this lesson, we learn about light emitting diodes (LEDs), including what they are made of and how they work. We then explore their practical applications in our everyday lives.

### 20. Piezoelectric Effect: Definition & Applications

In this lesson, we look at the piezoelectric effect and some of its fascinating applications. Also, we use the ideas of material structure and electric dipole moments to explain how this effect works.

### 21. Voltage Spike: Definition, Causes & Protection

When working with circuits or any other electrical components, you have to protect your equipment from voltage spikes and surges that can damage or destroy your components. Learn why and what you can do in this lesson.

### 22. Active vs. Passive Components in Electronics

Open up your computer and you'll see some circuit boards with all kinds of little components. In this lesson, you'll learn which components are considered passive or active and which one you need for your electronics to work.

### 23. What is RFID? - Definition & Applications

Did you know that you can find RFID chips everywhere from your hotel key card to the clothes tag at the department store? RFID has many uses from tracking inventory to tracking people. Learn how in this lesson.

### 24. What is an Antenna? - Definition & Uses

Discover the different kinds of antennas and how they work, along with their specific applications and the science behind generating waves. Explore the difference between AM and FM waves.

### 25. Radio Wave: Definition, Spectrum & Uses

Radio waves are used in almost all forms of wireless communication, and you certainly utilize them every day! In this lesson, learn more about how radio waves are produced, and then learn about the different types of radio waves and how they are used.

### 26. What is a Transistor? - Definition, Function & Uses

In this lesson, we will learn about transistors by exploring their characteristics. We will then look at how they work and find out why they are the key to modern electronics.

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### Other Chapters

Other chapters within the Introduction to Engineering course

- Materials & Properties in Engineering
- Stress & Strain in Engineering
- Temperature & Heat in Engineering
- Tools & Processes in Engineering
- Pressure in Engineering
- Tolerance in Engineering
- Basics of Structural Engineering
- Basics of Chemical Engineering
- Electrodynamics
- Physics Concepts in Engineering
- Acoustics in Engineering
- Building Construction & Properties in Engineering
- Electrical Interference in Engineering