David Chen
Soldering specialist and IPC-certified trainer.
Published work
Showing the latest 60 — browse the full index in the sitemap.
Components & PrototypingBest Free PCB CAD Software: Trace Sizing and First-Spin Testing
Compare top free PCB CAD software for makers. Includes trace width vs current tables, breadboard migration checklists, and first-spin testing protocols.
Projects & AutomationDesigning an Open Source Robot Platform with ROS 2 and ESP32
Learn how to architect an open source robot platform using ROS 2, Raspberry Pi, and ESP32, with real power budgets and debugging walkthroughs.
Components & PrototypingHow Amplification Sound Works: Audio Power, Gain, and Amp Classes
Understand how amplification sound works. We break down audio power, voltage gain, amplifier classes (A, AB, D), and real-world circuit calculations.
Projects & AutomationOpen Source Robotic Platform Guide: ROS 2 Hardware and Power Budgets
Learn how to architect an open source robotic platform using ROS 2, ESP32, and Raspberry Pi. Includes power budgets, CAN bus wiring, and hardware selection.
Projects & AutomationBulletproof Code for Arduino HC-SR04 Ultrasonic Sensors
Get robust, non-blocking code for Arduino HC-SR04 ultrasonic sensors with I2C LCD output. Includes wiring, error handling, and debugging steps.
Switches & OutletsHow to Install a Circuit Breaker Box: 100A Subpanel Wiring Guide
Learn how to install a circuit breaker box for a 100A subpanel. Includes wire sizing, color-coded termination steps, and testing procedures.
Switches & OutletsHow to Wire a Standard 15A Electrical Wiring Outlet: Step-by-Step
Learn how to safely install a 15A electrical wiring outlet. Includes wire gauge specs, color-to-terminal mapping, meter testing, and common mistakes.
Components & PrototypingUnderstanding Basic Binary Numbers in Digital Circuits and Microcontrollers
Learn how basic binary numbers dictate voltage states, GPIO logic, and shift register operations in real-world digital circuits and microcontrollers.
Components & PrototypingMastering Protocol Communication: I2C, SPI, and UART Bus Mechanics
Compare I2C, SPI, and UART protocol communication. Covers bus mechanics, pull-up wiring, debug sniffing, and classic hardware failure modes.
Components & PrototypingWhat Are Diodes Used For in Circuits? Practical Guide & Default Parts
Discover what diodes are used for in circuits, from rectification to flyback protection. Includes default part numbers, testing steps, and application circuits.
Components & PrototypingDesigning an Astable Timer 555 Circuit: Topology, Tuning, and Failure Modes
Master the astable timer 555 circuit with node-level topology, a component behavior matrix, real-world design math, and breadboard failure analysis.
Components & PrototypingHow to Use a Resistor Calculator: Formulas, Worked Examples, and Part Selection
Master the resistor calculator with Ohm's and Power law formulas, step-by-step worked examples, unit trap avoidance, and a concrete part-selection decision tree.
Components & PrototypingTransitioning to PCB Layout Design Online: Trace Sizing, Migration, and First-Spin Testing
Master the transition from breadboard to manufactured PCB. Learn trace sizing, IPC-2221 current limits, first-spin testing, and online layout FAQs.
Projects & AutomationHow to Program on Raspberry Pi 5: I2C Sensor Dashboard & Debugging
Learn how to program on Raspberry Pi 5 using Python to read a BME280 sensor, display data on an SSD1306 OLED, and debug common I2C errors.
Components & PrototypingHow to Read an Electrical Diagram Schematic: Symbols, Logic, and Troubleshooting
Master the electrical diagram schematic. Learn standard symbols, trace logical nodes, and understand the critical differences between schematics and physical wiring.
Components & PrototypingVolts/Ohms Ratio: Sizing Resistors for 12V DC Circuits
Learn how the volts/ohms ratio dictates DC current flow. Includes worked math examples, real-world LED sizing, and a decision tree for picking parts.
Components & PrototypingThe Essential Trig Formulas List for AC Circuit Analysis & Power Triangles
Master the essential trig formulas list for AC circuits. Includes impedance and power triangle tables, worked examples, and unit tracking for real-world loads.
Switches & OutletsWiring a Ceiling Fan Switch: Electromechanical Relay Ratings & Setup
Master wiring a ceiling fan switch with our electromechanical guide. Learn relay contact ratings, coil wiring, and motor load testing for 2026 setups.
Switches & OutletsHow to Wire Up Outlet Receptacles: 15A vs 20A Decision Guide
Learn how to wire up outlet receptacles safely. Includes a 15A vs 20A decision tree, exact terminal mappings, wire prep, and multimeter testing steps.
Components & PrototypingMaster the Calculation of Electricity Bill: Formulas, Unit Traps, and Worked Examples
Learn the exact calculation of electricity bill with our formula breakdown, symbol maps, worked examples, and real-world workshop scenario analysis.
Components & PrototypingHome PCB Fabrication: Trace Sizing, Migration, and First-Spin Testing
Master home PCB fabrication with IPC-2221 trace width tables, breadboard migration checklists, and first-spin testing steps for reliable custom boards.
Components & PrototypingHow to Design Your Own PCB: Trace Sizing, Prototyping, and First-Spin Testing
Learn how to design your own PCB with IPC-2221 trace width tables, breadboard migration checklists, and first-spin testing procedures for reliable boards.
Projects & AutomationWhat Is a Ground Fault Interrupter? Safety Rules for Mains-Powered IoT Projects
Learn what a ground fault interrupter is, how it prevents lethal shocks, and the exact wiring rules for integrating GFCIs into mains-powered ESP32 or Arduino projects.
Components & PrototypingHow to Read an Electric Schematic: Symbols, Tracing, and Component Decisions
Learn how to read an electric schematic with this practical guide covering standard symbols, worked numeric examples, and decision trees for bench debugging.
Components & PrototypingPotentiometer English Terminology and Multimeter Testing Guide
Master potentiometer English terminology, pinouts, and multimeter testing. Learn exact probe placements, expected ohm readings, and diagnostic mistakes.
Components & PrototypingStep-by-Step Derivation of Voltage Divider Equation & Practical Design Guide
Master the derivation of the voltage divider equation, explore real-world ESP32 ADC scaling with E24 resistors, and learn extreme failure mode analysis.
Components & PrototypingUnderstanding the Electronics AND Gate: Logic, IC Specs, and Circuit Applications
Master the electronics AND gate with real-world IC specs, threshold calculations, and practical circuit interlock examples for 74HC08 and CD4081 chips.
Components & PrototypingHow to Design an RC Bandpass Filter: Cutoff Frequencies and Q Factor
Learn how an RC bandpass filter works, calculate exact cutoff frequencies with a real numeric example, and avoid common breadboard design pitfalls.
Components & PrototypingHow to Convert Fractional Binary to Decimal for DAC and ADC Precision
Learn how to convert fractional binary to decimal for precise DAC and ADC voltage control, featuring worked examples and resolution decision paths.
Components & PrototypingSelecting and Biasing a Light Emitting Diode Semiconductor: 2026 Guide
Learn to select, bias, and test a light emitting diode semiconductor. Includes circuit calculations, default part numbers, and multimeter testing steps.
Components & PrototypingHow the Boolean Operator OR Works in Digital Logic and Physical Circuits
Master the boolean operator OR with real-world circuit examples, 74HC32 logic thresholds, and a bench-tested ESP32 sensor interlock scenario.
Switches & OutletsKinds of Circuit Breaker: Circuit Topology, Fault Behavior, and Panel Sizing
Compare kinds of circuit breaker using circuit topology, fault behavior matrices, and a decision tree to size and select the right 20A breaker.
Components & PrototypingWhat Is Electricity? The Physics, Units, and Real-World Circuit Behavior
Understand what electricity is at the atomic level. We break down fundamental units, drift velocity, and real-world circuit calculations for makers.
Components & PrototypingUnderstanding the Inductor in Physics: From Magnetic Flux to Bench Selection
Bridge the gap between the inductor in physics theory and bench practice. Learn core selection, marking codes, failure modes, and safe substitution rules.
Switches & OutletsDesigning a Bench Test Circuit for a Mechanical Circuit Breaker Trip Curve
Learn how to design a safe bench-test circuit to map a mechanical circuit breaker's thermal trip curve using real component values and node topology.
Components & PrototypingUnderstanding Mains Power Voltage: RMS, Tolerances, and Wiring Decisions
Master mains power voltage with real-world tolerances, RMS vs peak calculations, and a decision tree for sizing 120V and 240V workshop circuits.
Projects & AutomationGetting Started with Raspberry Pi 5: First Hardware Project and I2C Debugging Guide
Master getting started with Raspberry Pi 5 hardware. Includes I2C pinouts, BME280 Python code, RP1 debugging, and exact error fixes.
Switches & OutletsHow to Wire a Breaker Panel: Adding a 30-Amp 240V Circuit
Learn how to wire a breaker panel for a 30-amp 240V circuit. Includes 10 AWG wire sizing, torque specs, termination steps, and safety testing.
Components & PrototypingDesigning a Capacitance Series String for High-Voltage DC Bus Filtering
Learn how to design a capacitance series string for 800V DC buses. Includes real component values, balancing resistor math, and failure mode analysis.
Components & PrototypingAC Meaning in Electrical Systems: RMS, Peak Voltages, and Practical Circuit Behavior
Understand the AC meaning in electrical systems. Learn how RMS, peak voltage, and frequency impact real-world wiring, breaker sizing, and component selection.
Components & PrototypingMastering the 555 Timer Texas Instruments NE555: Pinouts, Circuits, and Testing
A practical guide to the 555 timer Texas Instruments NE555, covering pinouts, astable/monostable circuits, safe default part numbers, and multimeter testing.
Projects & AutomationPractical Arduino Code Projects: Building a Fault-Tolerant BME280 I2C Logger
Master practical Arduino code projects by building a fault-tolerant BME280 I2C weather logger. Includes wiring, C++ code, and I2C debugging.
Switches & OutletsWhat Is the Resistance of a Wire? Sizing, Voltage Drop, and Real-World Calculations
Learn what the resistance of a wire is, how to calculate voltage drop with real numbers, and how to pick the right AWG size for long electrical runs.
Components & PrototypingMastering Examples of Resistors in Series: Exam Walkthrough & Traps
Walk through practical examples of resistors in series with step-by-step algebra, KVL verification, and common exam traps for circuit analysis.
Switches & OutletsWiring a GFI Breaker: Electromechanical Specs, Line/Load Paths, and Trip Curves
Master wiring a GFI breaker with our electromechanical guide. Covers internal trip coils, line/load torque specs, and load-type selection for 2026 panels.
Components & PrototypingTranslating Boolean Logic Equations to Physical CNC Interlocks: Delays, Fan-Out, and IC Selection
Derive boolean logic equations for hardware interlocks, track propagation delays in nanoseconds, and select the exact 74-series IC for your circuit.
Components & PrototypingUnderstanding the 6 Bit Binary Number in PWM and DAC Circuits
Learn how a 6-bit binary number dictates circuit granularity in DACs and PWM, with real-world math, bench scenarios, and overflow troubleshooting.
Projects & AutomationUsing an Oscilloscope with Raspberry Pi: A GPIO Debugging Guide
Learn how to use an oscilloscope with Raspberry Pi to debug I2C, SPI, and GPIO signals. Includes probe setup, expected readings, and tool picks.
Projects & AutomationInterfacing Next-Gen Sensors Technologies with ESP32: BME688, SCD41, and 4-20mA
A hardware interfacing guide for modern sensors technologies on ESP32, covering I2C digital parsing, 4-20mA analog loops, and raw-to-unit math.
Components & PrototypingElectric Motor Designs: Load Profiling and Drive Selection Guide
Learn how to match electric motor designs to specific load profiles, size drivers, wire terminals, and diagnose hum, overheat, and stall failures.
Switches & OutletsPrinted Wiring Board Design for Custom Home Automation Control Panels
Learn the core principles of printed wiring board design for custom home automation panels, including trace ampacity, mains clearances, and layout rules.
Projects & AutomationRaspberry Pi Pico W I2C BME280 Wiring and MicroPython Error Fixes
Wire a BME280 to a Raspberry Pi Pico W over I2C. Includes exact MicroPython code, pinouts, and fixes for Errno 19 and Errno 110 I2C errors.
Components & PrototypingParallel Resistance Calculations for Custom Circuit Loads
Master parallel resistance calculations to design custom loads. Includes node topology, failure modes, and a breadboard testing walkthrough.
Switches & OutletsHow to Wire Up a Breaker Box for a 240V Circuit: Sizing, Steps, and Testing
Learn how to wire up a breaker box for a 240V, 30A circuit. Includes exact wire gauges, breaker sizing, color-coded termination steps, and meter testing.
Components & PrototypingHow Electricity Is Generated: From Grid Alternators to DIY Micro-Hydro
Learn how electricity is generated via electromagnetic induction, with worked numeric examples for sizing DIY alternators and off-grid power systems.
Projects & AutomationHow Does a PWM Work? Duty Cycles, Frequencies, and Microcontroller Control
Learn how PWM works with real numeric examples. Master duty cycles, frequencies, and pick the right microcontroller settings for motors and LEDs.
Components & PrototypingHow to Derive the Voltage Divider Equation: Topology, Design, and Failure Modes
Learn how to derive the voltage divider equation, select real E24 component values for ESP32 ADCs, and analyze circuit failure modes.
Components & PrototypingHow to Use a Color Band Resistor Calculator: Formula Derivation & Worked Examples
Master the color band resistor calculator formula. Includes symbol tables, reverse-engineering derivations, unit tracking, and a concrete part selection guide.
Projects & AutomationMastering the Arduino ESP32 Core: Dual-Core Sensor Node Build
Build a dual-core IoT sensor node using the Arduino ESP32 core. Includes exact pinouts, compilable code, and fixes for common ESP32 upload errors.
Components & PrototypingTrigonometry Geometry Definition: Decoding AC Power Triangles and Phasors
Master the trigonometry geometry definition for AC circuits. Learn how impedance triangles, phasors, and power factor calculations prevent real-world wiring failures.