Electronics guides
Clear, worked-example guides to the questions that come up at the workbench — written for makers, students and anyone fixing or building a circuit.
- Reading Resistor Color Bands Without GuessworkRead 3, 4, 5 and 6-band resistor color codes: which end to start from, the full color table, worked examples and how to confirm a value with a multimeter.
- How to Decode the Numbers on SMD ResistorsDecode surface-mount resistor markings: 3-digit and 4-digit codes, R notation, EIA-96 letter codes, zero-ohm jumpers, unmarked chips and package power ratings.
- Choosing the Right Series Resistor for an LEDWork out the series resistor for any LED with R = (Vs − Vf) / I. Forward voltage table, 5 V, 3.3 V and 12 V examples, power rating and MCU pin limits.
- Why Resistors Come in 4.7 kΩ and Not 5 kΩWhy resistors come in odd values like 4.7k and 5.6k: how the E3 to E192 series are built, how they match tolerance, full E12/E24 tables and combining values.
- How Many Watts Does Your Resistor Need?Calculate resistor power with P = V·I, I²R or V²/R, then pick a rating with a safety margin. Covers derating, pulses, burnt resistors and SMD package limits.
- Pull-Up vs Pull-Down Resistors for MicrocontrollersWhy floating inputs misbehave, how pull-up and pull-down resistors fix them, choosing 1k to 100k values, internal pull-ups, and sizing I²C pull-up resistors.
- How to Remember the Resistor Color CodeMemorise the resistor color code for good: mnemonics for the 10 digit colors, the rainbow trick, multiplier shortcuts and a graded practice set with answers.