Electronics & Circuit Toolkit

Electronics & Circuit Toolkit is an offline bench companion for hobbyists, students, technicians and audio builders. Work out values, decode markings and look up formulas without leaving the app. No ads, no account, no internet connection needed.

43 CALCULATORS
- Electrical: Ohm's law, DC power, series and parallel resistance, voltage and current dividers, loaded voltage divider, resistor dissipation, wire resistance, resistor pair finder
- Components: resistor color bands, band lookup, SMD resistor codes, EIA-96 codes, capacitor codes, resistor E-series, capacitor and inductor networks, capacitive and inductive reactance, LC resonance
- Timing and filters: RC and RL time constants, RC low-pass and high-pass cutoff, RL filter cutoff, frequency and period
- LEDs: series resistor, array planner, resistor comparison, string balance
- Batteries: energy, runtime, pack builder, C-rate, charge time, load profiles
- Audio: speaker impedance, audio power, decibel converter, first-order crossover, speaker wiring scenarios, crossover component finder

SEE THE WORKING
Every tool shows its formula, your values substituted in and the steps to the answer. Choose units from dropdowns with metric prefixes, and set how many decimals to show. Resistor values come with color band previews, and many tools draw a schematic or a response curve.

REFERENCE LIBRARY
39 offline reference cards in 8 packs, including circuit symbols, resistors, capacitors and inductors, signals, batteries and LEDs, audio, and SI units. Search tools and references together, and star your favorites for quick access.

PROJECTS AND HISTORY
Save results into projects with notes and worksheets, start from templates, and duplicate or rename projects. Your last 100 calculations are kept in history, and you can resume a calculator you left unfinished.

YOUR DATA STAYS ON YOUR DEVICE
Everything is stored locally. Create backups and restore them later. Copy results as text or CSV, save diagrams as images, and export or import whole projects as JSON.

BUILT FOR PHONE AND TABLET
Layouts adapt to phones and tablets, with dark, light and system themes, a choice of gold, blue or teal accents, and adjustable text size. Main menus and settings can be switched to French or Spanish; calculators and reference cards are in English.

GOOD TO KNOW
Calculations use ideal-component formulas and are estimates. Real parts have tolerances, temperature effects and limits, so always check the datasheet and apply proper derating and protection. This app is not a circuit simulator or a safety certification tool.