Charts and Tools
The reference tables everyone ends up needing at step three of a project, plus two tools for when you don't know what you're holding.
What component is this?
A few questions about shape, markings and legs, and the mystery part in the drawer has a name.
Ohm's law wheel
The classic twelve-formula wheel, drawn big and tappable.
AWG wire chart
Diameter, resistance and how many amps each gauge carries, from AWG 4 to 30.
Standard resistor values
The E12 and E24 series, and why 470 exists but 450 does not.
Capacitor conversion table
pF, nF and uF lined up so you stop counting zeros, with the common codes.
Schematic symbols
What every squiggle in a circuit diagram means, in one place.
Battery sizes
From AAA to 18650 to coin cells: voltage, capacity and where each one shows up.
Made to print
Each chart fits on one page and prints clean in black and white, because the inside of a parts cabinet door is still the best reference display ever invented. The values come from the published standards, not from someone else's blog table.
Why these values are standardised
Resistor series, wire gauges and capacitor codes all exist to solve the same problem: manufacturers cannot stock every value, so the industry agreed on a ladder of them. Resistors follow the E series, spaced so each value's tolerance meets the next. Wire follows AWG, where every three gauge numbers doubles the copper area. Capacitors are marked in picofarads with a zero count. Once the pattern is clear, most of these tables stop needing to be looked up at all.
Printing these
Every chart is plain HTML with no background images, so a browser print gives clean black on white with no ink wasted. The tables fit a single page at default scale. The traditional home for them is taped inside a parts cabinet door, where the answer is visible while both hands are busy, which is exactly when nobody wants to unlock a phone.