Electronics
LED resistor calculator: what resistor for 12 V?
Work out the series resistor for an LED on 12 V, 5 V or any supply. Rounds up to a standard value and shows the current and the resistor's power.
Electronics
Components, circuits and the maths behind them, explained from the breadboard up.
3D Printing
The best free 3D prints for October 2026
Ten free 3D prints for October 2026: five for Halloween and five you will still use in January, with print tips and what people who printed them report.
Electronics
Charging Lithium Cells with a Bench Power Supply
How to charge a lithium cell safely from a bench power supply: read the datasheet, set the voltage and current, and know when to stop.
Electronics
555 timer astable: flashing an LED on a breadboard
Wire a 555 timer in astable mode to flash an LED, with the frequency and duty cycle calculated for the parts used and a diagram to copy.
Electronics
Make a simple LED circuit on a breadboard. (Maths included)
Build a one-LED circuit on a breadboard and use Ohm's law to pick the right resistor, with the maths worked through step by step.
Electronics
Capacitors: What They Are and How They Work
What a capacitor is, how it stores energy, the main types and uses, and how to work out total capacitance in series and in parallel.
Electronics
What are resistors & how do they work?
What a resistor does, Ohm's law, colour codes and materials, with worked examples of a voltage divider and choosing a resistor for an LED.