Work it out.
Calculators
Frequency converter (Hz ↔ A/h)
Definition: 1 Hz = 1 svingning/sek
Gear ratio (gears)
Tandhjulslære: R = drevet/drivende
Rate deviation
COSC-krav: −4 til +6 sek/dag
Water resistance (ATM → metres/bar)
Hydrostatik: 1 ATM ≈ 10 m vandsøjle
Amplitude from tick-tock (timegrapher)
Timegrapher-formel (Vibrograf/Witschi-branchestandard)
Barrel turns (mainspring)
Geometri (spiral-tilnærmelse: L ≈ N × π × middeldiameter)
Regulation — hairspring adjustment
Fysik: T = 2π√(I/κ), κ ∝ 1/L (regulator-effekt)
Quartz accuracy (ppm → seconds)
Definition: 1 ppm = 1 dels-million afvigelse
Battery life (quartz watch)
Producentdata (batteridatablad: typisk 5–40 mAh, 0,2–2 µA hvilestrøm)
O-ring compression (caseback gasket)
Tætnings-tommelfingerregel: 15–30% klemning (statisk O-ring)
Loupe magnification (dioptres ↔ x magnification)
Optik: nærpunktsregel M = 250 mm / f
Dial index division
Geometri: cirkeldeling 360°/n
Chain adjustment (number of links to remove)
Ratio arithmetic
Spherical glass — dome height (sagitta)
Geometri: sagitta-formel (kuglehætte)
Repair quote (service + parts)
Procentregning
Thread — metric micrometer screw (minor and pitch diameter)
ISO 68-1 / ISO 724 metrisk gevindgeometri
Tools that work in all subjects
Whatever your programme is called, these tools calculate the same — Pythagoras, area, percentages and units are not tied to one trade.
- Pythagorasa² + b² = c²Find the missing side, set out a right angle, check whether a room is square, and find the space diagonal.
- Area and perimeterm²Rectangle, triangle, trapezium, circle and composite shapes — area and perimeter.
- Volume and surface aream³ · lBox, cylinder, cone, sphere, pyramid, prism, pipe and frustum — also in litres.
- Percent%Percentage of, how many per cent, percentage change, discount and VAT.
- Scale and ratios1 : 50From drawing to reality, area and volume to scale, the rule of three and dividing in a ratio.
- Unit convertermm ↔ mFrom mm to km, Pa to bar and kB to GB — with the unit staircase.
- Time calculations and the clockt : minTime between two clock times, add time, and 1.75 h = 1 h 45 min for the timesheet.
- Slope and fall% · ° · 1:xFall from level to level, in per cent, per mille, degrees and mm per metre — and the height difference.
- Material consumption including wastem² + %Boards, paint, battens at c/c spacing and packs — for a composite surface or a whole room, with waste.