Ohmstead
Electronics bench & reference
$0.99 · Designed for iPad. Not verified for macOS.
One offline bench for the whole hardware lab: circuit calculators, resistor and SMD decoders, component pinouts, connector maps, and every standards table you reach for.
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.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Robert Corbin, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Robert Corbin
- Size
- 16.7 MB
- Category
- Developer Tools
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Robert Corbin
