Programming
Free QR code generator: static codes that never expire
Make free QR codes for links, Wi-Fi, email, phone numbers and texts. Static codes that never expire, with PNG and SVG downloads and code for your own site.
Articles, page 2
Tools
VAT calculator UK: add or remove VAT at 20% or 5%
Add VAT to a price or take it off at 20%, 5% or any rate. Shows the price without VAT, the VAT and the total, with the working.
Tools
Celsius to Fahrenheit converter, chart and gas marks
Convert Celsius to Fahrenheit or Fahrenheit to Celsius as you type, with the formula, quick mental methods, full charts and UK oven gas marks.
Technology
Top Ten Essential Windows Programs
Ten programs I install on every Windows PC, from an office suite and a browser to Notepad++ and FileZilla, with free alternatives where they exist.
Technology
Top Ten Windows Keyboard Shortcuts
Ten Windows keyboard shortcuts worth learning, from switching windows and showing the desktop to locking the PC and opening Task Manager.
Tools
How to take VAT off a price: divide by 1.2
To take 20% VAT off a price, divide it by 1.2. Here is why it works, why taking 20% off gives the wrong answer, examples, the 5% rate and spreadsheet formulas.
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.