Bench tools
Bench calculators
Quick calculations technicians do every day. Everything runs in your browser and works offline.
Ohm's law & power
Fill in any two values.
Enter exactly two values.
V = I × R · P = V × I. Lesson
Resistor colour code (4-band)
SMD code decoder
Resistors: 103, 4R7, R010, 1002, 01C (EIA-96). Capacitors: 104 = 100 nF.
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Battery watt-hours & flying
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Wh = V × Ah. Rules shown are general IATA thresholds; always check the airline.
Laptop battery pack voltage
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Standard Li-ion cells: 3.6–3.85 V nominal, 4.20 V full. High-voltage cells charge higher — check the pack label.
Voltage divider
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Vout = Vin × R2 ÷ (R1 + R2) — how regulators set their output.
Short-injection safety helper
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If the short is inside a big chip (CPU, PMIC, SoC), injection heats that chip. Diagnose and decide — don't cook it.
Repair price calculator
The default numbers are examples only — use your own costs and timed jobs.