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Electronics Engineering Cheat Sheet

The core ideas of Electronics Engineering distilled into a single, scannable reference — perfect for review or quick lookup.

PiqCue — piqcue.com/electronics-engineering/cheatsheet

Quick Reference

Ohm's Law

The fundamental relationship stating that the voltage across a conductor is directly proportional to the current flowing through it, expressed as $V = IR$, where $V$ is voltage in volts, $I$ is current in amperes, and $R$ is resistance in ohms.

Semiconductor Physics

The study of materials with electrical conductivity between that of conductors and insulators. Semiconductors like silicon and germanium can be doped with impurities to create n-type (electron-rich) or p-type (hole-rich) materials, forming the basis of all modern electronic devices.

Transistor Operation

A transistor is a semiconductor device that can amplify or switch electronic signals. In a bipolar junction transistor (BJT), a small base current controls a larger collector-emitter current. In a MOSFET, a gate voltage controls the channel conductivity between source and drain.

Kirchhoff's Laws

Two fundamental laws for circuit analysis. Kirchhoff's Current Law (KCL) states that the total current entering a node equals the total current leaving it. Kirchhoff's Voltage Law (KVL) states that the sum of all voltages around any closed loop in a circuit equals zero.

Operational Amplifiers

High-gain voltage amplifier ICs with differential inputs and a single-ended output. Ideal op-amps have infinite input impedance, zero output impedance, and infinite open-loop gain. With negative feedback, they form the building blocks of analog signal processing circuits.

Digital Logic

The foundation of digital electronics, using binary states (0 and 1) represented by voltage levels. Logic gates (AND, OR, NOT, NAND, NOR, XOR) perform Boolean algebra operations and are combined to build complex digital systems such as processors and memory.

Signal Filtering

The process of selectively passing or attenuating specific frequency components of an electronic signal. Filters are classified as low-pass, high-pass, band-pass, or band-stop and are implemented using combinations of resistors, capacitors, inductors, or active components.

Feedback Systems

Circuits where a portion of the output signal is returned to the input to control system behavior. Negative feedback reduces gain but improves stability, bandwidth, and linearity. Positive feedback increases gain and is used in oscillators and comparators.

Power Electronics

The branch of electronics dealing with the conversion and control of electrical power using semiconductor switching devices such as diodes, thyristors, MOSFETs, and IGBTs. Applications include AC-DC rectification, DC-DC conversion, and motor drives.

Embedded Systems

Dedicated computing systems designed to perform specific functions within larger electronic systems. They combine a microcontroller or microprocessor with firmware, memory, and input/output peripherals, operating under real-time constraints.

Key Terms at a Glance

Alternating Current (AC):Electric current that periodically reverses direction, typically in a sinusoidal waveform, characterized by its frequency and amplitude.
Amplifier:A circuit that increases the power, voltage, or current of a signal, using energy from a power supply to produce a larger replica of the input.
Bandwidth:The range of frequencies over which a circuit or system operates effectively, typically defined between the $-3$ dB points.
Capacitor:A passive component that stores energy in an electric field between two conductive plates separated by a dielectric material.
CMOS:Complementary Metal-Oxide-Semiconductor technology using paired n-channel and p-channel MOSFETs for low-power digital circuits.
Current:The rate of flow of electric charge, measured in amperes (A). Conventional current flows from positive to negative.
Depletion Region:The zone at a p-n junction devoid of mobile charge carriers, creating an internal electric field that opposes further diffusion.
Diode:A two-terminal semiconductor device that allows current to flow primarily in one direction, from anode to cathode.
Direct Current (DC):Electric current that flows consistently in a single direction, maintaining a constant polarity.
Duty Cycle:The fraction of one period in which a signal is active or HIGH, expressed as a percentage. Used extensively in PWM.
Electromotive Force (EMF):The voltage generated by a source of electrical energy such as a battery or generator, measured in volts.
Gain:The ratio of output to input of a signal property (voltage, current, or power) in an amplifier, often expressed in decibels.
Ground:The reference point in a circuit against which all voltages are measured. May be earth ground or a circuit common.
Impedance:The total opposition to alternating current, combining resistance and reactance as a complex quantity: $Z = R + jX$, measured in ohms.
Inductor:A passive component that stores energy in a magnetic field when current flows through its coil of wire, measured in henrys.

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Electronics Engineering Cheat Sheet - Quick Reference Guide | PiqCue