Work it out.
Calculators
Ohm's law and power
Ohm's law
Voltage divider
Spændingsdeler-reglen
RC time constant
RC time constant
Voltage drop in a cable
ΔU = 2·ρ·L·I/A
Resistor colour code (4-band)
IEC 60062 (farvekode-standard for modstande)
LED series resistor
Ohms lov / LED-databladsformel
Capacitive reactance (Xc)
Reaktansformel (vekselstrømsteori)
Inductive reactance (XL)
Reaktansformel (vekselstrømsteori)
RC low-pass filter cut-off frequency
Filterformel (RC-lavpasfilter)
Parallel resistors
Parallelmodstands-formel (Ohms lov)
PCB track width for current
IPC-2221 (PCB-designstandard)
Heat sink and junction temperature
Termisk Ohms lov (halvleder-/køleplade-datablad Rth)
Transformer turns ratio
Transformerformel (induktionslov)
Battery runtime
Kapacitetsregning (batteri-databladsformel)
Quarter-wave antenna length (λ/4)
Antenneformel (λ/4-monopol, radioteknik)
Bent bracket
Exact flat pattern
Edge-bent panel
Exact flat pattern
Cable tray
Exact flat pattern
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.