Ohmstead

About Ohmstead

Ohmstead is a complete electronics reference and calculator bench that runs entirely on your device. It gathers the lookups and math a hardware engineer, repair tech, maker, or student reaches for dozens of times a day into one clean, ad-free workspace that works on a plane, in a lab with no signal, or in the field.

Everything is bundled on device. There is no account, no login, and nothing to fetch from a server.

WHAT'S INSIDE

Calculators (44 tools)
• Ohm's law and power, voltage and current dividers, series/parallel networks
• LED series resistor, zener regulator, and battery runtime
• Capacitive and inductive reactance, LC resonance, series-RLC Q and bandwidth
• RC and RL filter cutoffs, Sallen-Key corner, RMS and peak conversions
• 555 astable and monostable, RC time constants
• Op-amp gain (inverting and non-inverting), gain-bandwidth, slew-rate limit
• Wavelength and antenna lengths, coax and microstrip impedance, skin depth, VSWR
• PCB trace width (IPC-2221), wire voltage drop
• Buck/boost duty, transformer turns, capacitor and inductor energy, junction temperature
• ADC resolution, PWM average, frequency and period
• Wheatstone bridge, NTC thermistor, air-core inductor

Decoders
• Interactive 4, 5, and 6-band resistor color code with a live resistor preview
• SMD code lookup: 3-digit, 4-digit, and EIA-96

Component & connector library
• Hundreds of real parts with pinouts and specs: 74xx and 4000 logic, op-amps and comparators, voltage regulators, BJTs and MOSFETs, diodes, zeners, LEDs, and popular microcontrollers
• Connector pinouts: USB-A/C, HDMI, VGA, DB9, RJ45, SATA, microSD, SWD/JTAG, the Raspberry Pi 40-pin header, ATX power, and more
• Part cross-reference for common substitutes

Standards tables
• E6 through E192 preferred values, each with full color bands, SMD codes, nearest-neighbor cross-references, and power ratings
• Capacitor 3-digit code decoder
• AWG wire table with diameter, resistance, and ampacity
• IPC-2221 PCB trace width
• Reactance/impedance chart for standard capacitor and inductor values across frequency
• SI prefixes, physical constants, a decibel ladder, logic-family levels, dielectric types, and battery chemistries

Bench sheets
• Save any calculation as a named bench sheet and pin your favorite calculators to the home screen

Built for engineers who want their reference material to be accurate, fast, and always available.