# Electronics in FE Electrical Exam

Electronics in the FE electrical exam is a critical area of study for the FE Electrical exam course per the NCEES® guidelines. Whether you’re an engineering student looking forward to appearing in the FE electrical exam or a seasoned professional looking to enhance your understanding of electronics, this study guide on electronics in FE electrical exam will be an invaluable resource in your exam preparation journey.

Electronics is a required field in electrical engineering, encompassing electronic circuits and systems’ principles, components, and applications. It plays a pivotal role in modern technology, from the devices we use daily to complex industrial systems.

To succeed in the FE Electrical Exam, it is crucial to have a solid grasp of electronics and its various subtopics, including essential electronic components, circuit analysis techniques, semiconductor physics, digital electronics, power electronics, and more.

In this study guide for electronics in the FE electrical exam, you’ll find a wealth of technical knowledge, practical examples, and problem-solving techniques to enhance your understanding of electronics and the physics involved in solid-state electronic devices.

Let’s dive in and embark on this exciting journey of mastering electronics for the Electrical FE Exam.

## Basic Electronics Principles

Understanding electronics in FE electrical exam requires understanding some fundamental electronics principles. Let’s start with some basics of devices used in electronics to uncover techniques and electronics accounts crucial to gain a firm grip on the mathematical approach to these devices.

### Components and Devices Used in Electronics

The table below outlines the critical devices used in electronics that you must acknowledge to master electronics for the Electrical FE exam.

### Circuit Analysis – Laws and Techniques

Circuit analysis in the FE electrical exam helps you uncover and solve hidden mysteries of complex electronic circuits. The table below highlights the crucial mathematical techniques used for electronics in the FE Electrical exam.

Consider adding a circuit with a voltage source of 24V to a bulb with resistance 6Ω. Let’s see how to calculate the voltage-current (I) and power (P) across the bulb (Resistor).

We have:

• Voltage source (V) = 24V
• Resistance of bulb (R) = 6Ω

We can find the current flowing through the resistor using Ohm’s Law (V = I  R).

V = I * R

24V = I * 6Ω

Solving for I:

I = 24V / 6Ω

I = 4A

To calculate the power (P) across the resistor, we can use Watt’s Law (P = V * I).

P = V * I

P = 24V * 4A

P = 96W

Therefore, the current through the bulb is 4A, and the power dissipated across it is 96W.

To master circuit analysis and learn different techniques for solving complex electrical and electronic circuits, read our comprehensive study guide on Circuit Analysis in the FE Electrical exam.

## Semiconductor Devices

Semiconductor Diodes are the most critical solid-state electronics devices that lay the foundation of electronics and solid-state physics.

Diodes are semiconductor devices (devices used in electronics having properties of both insulator and conductor based on their configuration) that allow current to flow in one direction while blocking it in the opposite direction. They are made by combining P-type and N-type semiconductors.

### Doping – Turning Materials into Semiconductors

Doping involves intentionally adding impurities to a pure semiconductor material to alter its electrical properties. Two common types of doping are used in making two different types of semiconductor diodes:

• P-type semiconductor – This is achieved by adding trivalent impurities (materials of Group 3 such as boron) to the pure semiconductor material, creating a deficiency of valence electrons (holes).
• N-type semiconductor –  This is achieved by adding pentavalent impurities (materials of Group 4 such as phosphorus) to the pure semiconductor material, introducing extra valence electrons.

### PN Junction – Making a Semiconductor Diode

When a P-type and an N-type semiconductor are combined, a PN junction or diode is formed. The region near the junction behaves differently from the P and N regions:

Forward Bias (Closed Switch/ON) – When a positive voltage is applied to the P side and a negative voltage to the N side, the diode is forward-biased. This reduces the potential barrier at the PN junction, allowing current to flow easily through the diode.

Reverse Bias (Open Switch/OFF) – When a positive voltage is applied to the N side and a negative voltage to the P side, the diode is reverse-biased. This increases the potential barrier, preventing significant current flow through the diode.

To understand the structure and foundation of semiconductor diodes and solid-state electronic devices, read our detailed guide on the Properties of Electrical Materials in the FE Electrical exam.

### Bipolar Junction Transistors (BJTs)

BJTs are three-layer semiconductor devices with two PN junctions. They are commonly used as amplifiers and switches in electronic circuits. BJTs have three terminals: the emitter (E), the base (B), and the collector (C).

Reverse Bias – In the reverse bias configuration, the base-emitter junction is reverse biased, and the transistor is in the off state. Only a small leakage current flows.

Forward Bias – The base-emitter junction is forward-biased in the forward bias configuration, allowing a current to flow through the base-emitter junction. This current control a much larger current flow between the collector and emitter, making the transistor behave as an amplifier or switch.

### Transistor Operation and Amplification

Transistors are made using epitaxial growth, where layers of different materials are deposited on a substrate to create the desired transistor structure. The most common type of transistor is the bipolar junction transistor (BJT).

Transistors work as amplifiers by controlling the current or voltage between the collector and emitter terminals based on the current or voltage applied to the base terminal. The transistor can amplify weak signals to high amplitude by adjusting the base current or voltage.

### Transistor Configuration

There are two types of transistor configurations in electronic circuits.

1. Common Emitter (CE) Configuration

In the common emitter configuration, the emitter terminal is shared between the input and output sides of the transistor. This configuration provides voltage amplification and current gain.

Characteristics

• High voltage gain and current gain.
• Inverts the input signal phase at the output.
• Moderate input impedance and relatively high output impedance.

Let’s consider a common emitter amplifier circuit with the following parameters:

• DC bias voltage at the base (Vb) = 1V
• DC bias voltage at the emitter (Ve) = 0.7V
• Base resistor (Rb) = 10kΩ
• Collector resistor (Rc) = 1kΩ
• Transistor current gain (β) = 100

We want to calculate the DC collector current (Ic) and the DC collector voltage (Vc).

Calculate the base current (Ib) using Ohm’s Law:

Ib = (Vb – Ve) / Rb

Ib = (1V – 0.7V) / 10kΩ

Ib = 0.3V / 10kΩ

Ib = 30μA

Calculate the collector current (Ic) using the current gain (β):

Ic = β * Ib

Ic = 100 * 30μA

Ic = 3mA

Calculate the collector voltage (Vc) using Ohm’s Law:

Vc = Vcc – (Ic * Rc)

(Vcc is the supply voltage)

Assuming Vcc = 10V,

Vc = 10V – (3mA * 1kΩ)

Vc = 10V – 3V

Vc = 7V

Therefore, in this common emitter configuration, the DC collector current is 3mA, and the DC collector voltage is 7V.

1. Common Collector (CC) Configuration:

In the common collector configuration, the collector terminal is common between the input and output sides of the transistor. This configuration provides voltage gain close to unity and current gain.

Characteristics:

• High input impedance and low output impedance.
• No phase inversion between input and output.
• Voltage gain close to unity (less than 1).

Let’s consider a typical collector amplifier circuit with the following parameters:

• DC bias voltage at the base (Vb) = 1V
• Base resistor (Rb) = 10kΩ
• Emitter resistor (Re) = 1kΩ
• Transistor current gain (β) = 100

We want to calculate the DC emitter current (Ie) and the DC emitter voltage (Ve).

Calculate the base current (Ib) using Ohm’s Law:

Ib = Vb / Rb

Ib = 1V / 10kΩ

Ib = 0.1mA

Calculate the emitter current (Ie) using the current gain (β):

Ie = (β + 1) * Ib

Ie = (100 + 1) * 0.1mA

Ie = 101 * 0.1mA

Ie = 10.1mA

Calculate the emitter voltage (Ve) using Ohm’s Law:

Ve = Ie * Re

Ve = 10.1mA * 1kΩ

Ve = 10.1V

Therefore, the DC emitter current (Ie) is 10.1mA, and the DC emitter voltage (Ve) is 10.1V.

### Transistor as an Amplifier – Use-Case

In audio systems, transistors amplify weak audio signals to drive speakers. An audio amplifier circuit typically consists of a pre-amplifier stage to amplify the weak audio signal and a power amplifier stage to provide sufficient power to drive the speaker.

The pre-amplifier stage amplifies the voice signal from a microphone or audio source. The amplified signal is then fed into the power amplifier stage, where the transistor amplifies it further to a level suitable for driving the speaker.

By controlling the input signal, the transistor amplifies the voice signal to a level that can produce the desired loudness and clarity when played through the speaker. This allows for better sound quality and ensures the speaker can produce sufficient volume for the intended application.

## Analog Electronics

Analog electronics deals with continuous signals representing real-world quantities such as voltage, current, and temperature. It focuses on designing, analyzing, and applying electronic circuits that process and manipulate analog signals.

In contrast to digital electronics (discussed in the upcoming section), which deals with discrete levels (0s and 1s), analog electronics handle signals with a continuous range of values.

Operational amplifiers (op-amps) are versatile integrated circuits widely used in analog electronic circuits. They are highly linear and have high gain and input impedance. Op-amps can perform various functions, such as amplification, filtering, mixing, and signal conditioning.

Op-amps have two input terminals – the inverting terminal (marked with a negative sign) and the non-inverting terminal. The output is taken from the output terminal, and a feedback mechanism connects the output back to the input terminals.

Below are some critical use cases of op-amps in electronic circuits.

• Signal amplification and conditioning – Op-amps are widely used for amplifying weak signals to a desired level, making them suitable for applications such as audio amplifiers and sensor signal conditioning. They can provide high gain and precise amplification of signals, improving the signal-to-noise ratio and ensuring an accurate input representation.
• Summing and differencing signals – Op-amps can sum or subtract multiple input signals, making them useful for applications like audio mixers and instrumentation amplifiers. By combining multiple input signals in a controlled manner, op-amps allow for signal combining, difference measurement, and signal extraction.
• Voltage/Current conversion – Op-amps can convert voltages to currents (and vice versa) using appropriate circuit configurations. This capability is essential in various applications, such as analog-to-digital converters (ADCs), transducers, and sensor interfacing, where conversion between voltage and current signals is required.
• Active filters and equalizers – Op-amps are extensively used to design active filters and equalizers that shape and manipulate the frequency response of signals. By combining op-amps with passive components like resistors and capacitors, active filters can achieve precise frequency selectivity, gain control, and impedance matching in applications like audio processing, telecommunications, and signal conditioning. Discover more about Transient Response in the FE Electrical exam.
• Comparators and voltage comparators – Op-amps configured as comparators compare two input voltages and produce a binary output based on their relative magnitudes. This functionality is valuable in voltage level detection, threshold detection, and signal threshold triggering applications.
• Oscillators and waveform generators – Op-amps, in combination with passive components, can generate periodic waveforms and oscillations. They are the building blocks of various oscillator circuits, such as sine wave oscillators, square wave generators, and pulse wave generators. These circuits find applications in signal generation, clock circuits, frequency synthesis, waveform testing, and other critical areas of Resonance in the FE electrical exam.
• Voltage regulators – Op-amps are used in voltage regulator circuits to provide stable and regulated output voltages. They are employed in linear and switching voltage regulators, contributing to voltage stabilization, load regulation, and protection against voltage fluctuations.
• Instrumentation amplifiers – Op-amps design instrumentation amplifiers that offer high common-mode rejection, low input bias current, and high input impedance. These amplifiers are particularly useful in measuring weak signals from sensors, medical instrumentation, data acquisition systems, and bridge circuits.
• Logarithmic amplifiers – Op-amps can be configured as logarithmic amplifiers, which convert input signals into logarithmic response outputs. Logarithmic amplifiers find applications in audio, signal, and other logarithmic scaling tasks.
• Voltage-controlled oscillators (VCOs) – Op-amps can be incorporated into VCOs to generate oscillating signals whose frequency can be controlled by a voltage input. VCOs are integral in applications such as frequency modulation (FM), phase-locked loops (PLLs), and frequency synthesizers.

## Digital Electronics

Digital electronics deals with the representation, manipulation, and processing of digital signals, which are discrete and binary in nature (0s and 1s). It involves designing, analyzing, and implementing electronic circuits and systems that operate on digital signals, enabling functions such as logic operations, arithmetic calculations, data storage, and communication.

In digital electronics, boolean algebra provides a foundation for designing and analyzing logic circuits and expressing the behavior of digital systems.

Boolean algebra uses three basic logic operations: AND, OR, and NOT, represented by the symbols (∧), (∨), and (¬), respectively. These operations manipulate binary variables or logical states (0 and 1) to produce logical outcomes. Boolean algebra also includes additional operations such as NAND, NOR, and XOR, which can be derived from the basic operations.

Learn more about Boolean Algebra and its techniques in our detailed guide to discrete mathematics in the FE Electrical exam.

## Power Electronics

It focuses on the efficient and reliable manipulation of electric power for various applications, including power conversion, motor drives, renewable energy systems, electric vehicles, and industrial automation.

To delve deeper into rectification and AC-DC conversion techniques, I recommend reading our separate guide on Demand Calculations. This guide will provide a more detailed exploration of rectification methods, including half-wave rectification, full-wave rectification, and bridge rectification. Read to discover their principles, advantages, limitations, and practical considerations in different applications.

### Conclusion

Added by NCEES® as a core preparation area, electronics in FE Electrical Exam is crucial, and mastering its principles and applications is mandatory for your exam preparation. By understanding electronics, you’ll gain a solid foundation that will shape your career in electrical engineering.

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Licensed Professional Engineer in Texas (PE), Florida (PE) and Ontario (P. Eng) with consulting experience in design, commissioning and plant engineering for clients in Energy, Mining and Infrastructure.