BenchKit: Electronics Tools

BenchKit puts four everyday electronics calculations in one focused iPhone app. The calculators work offline. RESISTOR CODES Decode 3, 4, 5, and 6-band axial resistors by tapping the bands on a drawn resistor, or SMD codes (3-digit, 4-digit, EIA-96, R notation). See the tolerance range, IEC marking code, and standard E-series match. When a reading is probably reversed, one tap flips it. PCB TRACE WIDTH Estimate minimum internal or external copper trace width from current, copper weight, and allowed temperature rise, in millimeters or mils, or the current a given width can carry. Results outside the IPC-2221 chart range are flagged as extrapolations. VOLTAGE DROP Voltage drop, the drop as a share of the supply, voltage at the load, and power lost in the wiring. Enter the round-trip resistance, or wire gauge (AWG or mm²), length, and conductor temperature. VOLTAGE DIVIDER Ideal unloaded output voltage, divider current, per-resistor dissipation, output resistance, and what an optional load does to the output. Or enter a target voltage and get the closest E24/E96 resistor pairs with their worst-case output. Type values the way engineers write them: 4k7, 2R2, 100m, 3V3; the keyboard has keys for the letters. Laid out for iPhone Duo: on the open screen the answer and the inputs sit on either side of the fold. BENCHKIT PRO (optional one-time purchase) • Value to code: enter a resistance and see its color bands and SMD codes. • Trace resistance: add a trace length to get its resistance, voltage drop, and heat. • Wire size for a drop: set an allowed voltage drop and get the thinnest AWG and mm² wire that meets it. Sized for voltage drop only; the wire's current rating is yours to check. The four tools above are free and stay free. No account. No ads. No analytics. English, Simplified Chinese, and Japanese. BenchKit is a quick estimation tool. Always verify production designs against component datasheets, applicable standards, simulation, and physical validation.