OhmCraft: Electronics Tools

OhmCraft is an offline toolkit for electronics: the calculators you reach for at the bench, the component markings you need to read and the pinouts you look up. Every calculator shows its formula, the formula with your own values put in, and the assumptions behind it.

TOOLS
• Basics: Ohm's law & power, Voltage divider, Current divider, LED resistor
• Time and frequency: RC time constant, RL time constant, Reactance & impedance, LC resonance
• Power and wiring: Wire voltage drop, Battery runtime
• Conversions: SI prefix converter
• Codes: Resistor colour code, SMD resistor code, Capacitor code
• Components: Series & parallel, Standard values

REFERENCE
• Pinouts: NE555 timer, Single op-amp, Dual op-amp, 78xx regulator, 79xx regulator, LM317 regulator, USB 2.0 connectors, RJ45 Ethernet wiring
• References: Colour code chart, SI prefixes, E-series values, AWG wire sizes, Electronics formulas, Electrical units

MADE FOR THE BENCH
• Ohm's law & power: any two of voltage, current, resistance and power give the other two.
• Resistor colour code: 4, 5 and 6 bands to a value, and a value back to its bands.
• LED resistor: the next standard value up (E12, E24 or E96), with the real current and a power rating.
• SMD resistor code and Capacitor code: 3-digit, 4-digit and EIA-96 markings, and codes such as 4R7 or 104K.
• Engineering units such as 4.7 kΩ and 220 nF, metric or imperial, with 3 to 6 significant digits.
• A safety warning with every result at 50 V or more.
• Pinout diagrams drawn by the app, with pinch to zoom and a table of every pin.
• Search by name in your language, or by part number such as 7805 or LM358.
• Favorites, and a history kept on this phone only. Copy or share any result.
• Projects collect calculations, components and notes for one build (two in the free version).
• Light and dark themes, 18 languages, and a side-by-side layout on tablets and in landscape.

MARKED PRO
Some calculators and sheets carry a PRO mark: 12 advanced calculators, such as filters, 555 timers, op-amp gain and regulators, and 19 more reference sheets, such as Raspberry Pi GPIO, Arduino Uno and USB-C.
Premium features are coming soon. We're preparing additional features for a future update. Stay tuned!
Until then, you can choose to watch one ad to open any one of them until you close OhmCraft.

PRIVACY AND ADS
No account and no sign-in. Your calculations, history and projects stay on your phone: OhmCraft has no server and no analytics.
OhmCraft is free and shows Google AdMob banner ads on list screens only (Tools, Reference, History, Projects), never inside a calculator, beside the colour bands or over a diagram. No ad interrupts you: the only full-screen ad is one you choose to watch. Where the law requires it, you are asked for consent first. There are no purchases in this version.

OhmCraft's calculations are engineering aids. They do not replace safety standards, certified design or the part's datasheet.

Made by Mobile Castle.