Bench Starter Bundle
5 products in one ZIPThe reference pack, posters, labels, Formula Handbook and lab sheets.
Est. 2000 · Lessons, calculators and part pages
Learn electronics by actually working through the numbers.
262 free lessons across 13 departments, 10 calculators and hand-checked pinouts. Every lesson value is recomputed before the page goes live, so you can follow the working and check it yourself.
262 lessons10 calculators4 build systems8 printables
What are you trying to do?
Sound familiar?
Four bench problems, and the page that solves each one
The bands on this resistor make no sense.
You get the value, the tolerance range and the nearest standard part.
Resistor colour code calculator →My LED keeps burning out.
You get the resistor, the current it really gives and the wattage it needs.
LED resistor calculator →My divider reads low once it's connected.
You get the loaded output and a better pair of resistors.
Voltage divider calculator →Which leg is the collector?
You get each package's pin order and the datasheet page it came from.
Part pages →Three ways in
Guided Paths
Each guided path puts existing lessons in one order, so no lesson assumes something you haven't read yet.
New to electronics27lessons
Zero to First Circuits
You finish able to read a simple schematic, build it on a breadboard, measure it and light an LED safely.
Start the path →Making things60lessonsMaker Fast Track
Transistor and MOSFET switches, relays and motors, the 555 for timing and PWM, batteries and fuses.
Start the path →Studying for an exam61lessonsCircuit Analysis Exam Prep
Mesh and nodal analysis, the network theorems, transients, and AC up to resonance, Q and Bode plots.
Start the path →Repairing boards? Practical Repair & Test Bench, 34 lessons →
Start here
Twelve places to start
Twelve pages to start from, picked by hand.
Lesson
Ohm's law
V = IR at four depths, from intuition to where it breaks down.
Lesson
The resistor
How to size one, and how tolerance and temperature move its value.
Lesson
RC time constant
Charging curves, the 63 % rule and why real timers drift.
Lesson
LED circuits
Series strings, why parallel needs care, and when to use a driver.
Calculator
LED resistor
One LED or a string: the resistor, the real current and the wattage.
Calculator
555 timer
Astable and one-shot timing, and standard RA and RB for a target frequency.
Calculator
Voltage divider
Loaded output, tolerance spread and the best standard pair.
Part page
2N2222 pinout
Four variants, two opposite pin orders, checked against 7 maker datasheets.
Build system
555 LED flasher
Two LEDs take turns at 0.99 Hz from a 9 V battery, every value worked out.
Build system
Festival LED lights
An Arduino 8-LED chaser at 9.1 mA per LED, a PWM fade and a 12 V strip.
Guide
MOSFET for Arduino and ESP32
IRLZ44N, IRFZ44N, IRF520 or AO3400A, and which one a 3.3 V pin can switch fully on.
AI tool
Datasheet Guru
Ask a datasheet a question in plain English. Each answer cites the page and section.
Worked out and drawn
All 10 calculators →Five results from our calculator pages
With the same numbers the calculators print.
From the EIL Store
Printables for the bench
PDFs to print and keep beside the soldering iron. They use the same checked values as our calculators and part pages.
Parts-Bin Labels
7 label sets in 6 sheet layouts (43 PDFs)E12 and E24 resistor labels with the colour bands drawn on each, capacitor labels and blanks. A4 sticker sheets and Avery 5160 and 5167.
Electronics Quick Reference Pack
11 pagesColour code, E-series and SMD codes, capacitor codes, transistor and 8051 pinouts, everyday formulas.
DC Circuits Workbook
77 pages100 problems from Ohm's law to Thevenin and Norton, each with a full worked solution.
Formula Handbook
63 pages166 formulas, each with its symbols, units, a worked example and the lesson it comes from.
Bench Poster Set
6 posters, each in 3 paper sizes (18 PDFs)Colour code, SMD and capacitor codes, common pinouts, the Ohm's law wheel and logic gates.
Lab Notebook Templates
5 templates and 5 filled examples, A4 and US Letter (13 PDFs)Build log, test record, BOM worksheet, troubleshooting sheet and breadboard grid, each with a filled example.
ESP32 & Arduino Bench Reference
Edition 1.2, 21 pages, in A4 and US Letter (2 PDFs)Pinouts, boot pins, electrical limits, level shifting, module wiring and code for the ESP32-DevKitC V4 and the Arduino UNO, Nano and Mega, in 21 pages. Every figure is traced to the maker’s datasheet and cited on the page.
Instant download once payment is confirmedRupees through Razorpay (GST included) or US dollars through PayPalYour link works for 7 days, up to 5 downloadsRefund policy
The library
Browse all lessons →Two schools, 13 departments
Every department runs in curriculum order. Looking up one term? The glossary has 21 entries.
School of Fundamentals
6 departments · 127 lessonsHow it works
Three steps
Pick a topic or a job
Start from a guided path, a department, or the calculator for the value you need.
Follow the worked numbers
Each lesson works its examples step by step, and its figures are drawn from the same computed values.
Check it, then build it
Run your own values through a calculator, read the pinout, and print the reference for the bench.
TipKeep the calculator open beside the lesson. Change one input and watch which result moves. You'll learn the formula faster than by rereading it.
What we'd doNew to electronics? Start Zero to First Circuits and take the lessons in order, one or two a day. Get a basic multimeter before anything else and measure every circuit you build. Already building? Open the build system for your project and print its one-page card.
Why the numbers hold
How we check the numbers
Recomputed on every build
Lesson values aren't typed into the prose. A harness recalculates each one from a shared formula library, and a lesson whose value drifts doesn't ship.
Pinouts from the maker's datasheet
Each part page names the datasheet and page every pin order came from: 7 datasheets for the 2N2222, 6 for the 2N3904, 4 for the BC547.
Online since 2000
ElectronicsInfoline went online on 18 October 2000. Find a wrong number and we fix the page. Editorial policy · Contact
Questions
Short answers
What is ElectronicsInfoline?
A free electronics learning site, online since 2000. It has 262 lessons in 13 departments, 10 calculators, part pages with pinouts, build systems for whole projects, and Datasheet Guru, an AI tool that answers questions from a datasheet.
Is it free?
The lessons, calculators, part pages and build systems are free, with no sign-up. Datasheet Guru has a free daily allowance and paid plans. The printables in the store are paid downloads.
Where do the numbers come from?
Each value is computed from a shared formula library and recalculated on every build. Pinouts and limits come from the manufacturers' own datasheets, with the page cited.
Who is it for?
Beginners, makers, diploma and B.Tech students, and anyone repairing boards. Each of them has a guided path to follow.
How do the store downloads work?
Pay in rupees through Razorpay or in US dollars through PayPal. The download link appears as soon as the payment is confirmed and works for 7 days, up to 5 downloads.