Crossover frequency calculator

Input contract, response shape, and error behaviour

Values that are zero or negative fail with a message that the field must be a positive finite number, because the crossover formula divides by the product R C. Send a JSON object with two required fields. resistance is the ohmic value of the resistor in ohms; aliases R, ohms, and r_ohm are accepted so spreadsheet exports and typed forms can reuse names they already have. capacitance is the capacitor in farads, which for typical parts means scientific notation such as 1e-6 for one microfarad, 1e-9 for one nanofarad, or 4.7e-8 for forty-seven nanofarads; aliases C, farads, and c_f are accepted. Each field may arrive as a JSON number or as a numeric string. Missing keys, empty strings, NaN, and infinities fail with invalid_input naming the field. On success the body echoes the rounded resistance and capacitance, reports frequency_hz as the primary result in hertz, reports angular_frequency as one over tau in radians per second, reports time_constant as the product R C in seconds, and restates the formula string fc=1/(2*pi*R*C) with method rc_crossover so downstream code can branch without sniffing shapes. A successful API call is billed at $0.002 per item; validation failures are not charged.

Where an RC crossover calculator earns its keep

Use this landing when the search intent is the crossover frequency of an RC filter network, not an LC speaker network and not a complexity break-even. Teachers can pin the one-kilohm and one-microfarad case as an oracle that must remain one thousand over two pi hertz. Prefer a dedicated LC crossover tool when you have inductance and capacitance of a speaker network; prefer an RL cutoff tool when the energy store is a coil. This page answers only fc from R and C for a first-order RC stage. Audio tone stacks, guitar-pedal high-pass rumble filters, anti-alias RC pads in front of an analog-to-digital converter, photodiode transimpedance shunts, and physics-lab first-order demonstrators all start from the same two passives. Enter the parts you have, read frequency_hz, and only then decide whether to swap the decade box or the capacitor. Firmware configurators that expose a cutoff slider can call the prepaid endpoint from a build pipeline at $0.002 per successful item and store the returned hertz next to the bill of materials. Component values should stay inside the documented magnitude ceiling so Worker isolates remain safe; extreme products that overflow floating point still fail closed rather than inventing a frequency. Source inputs follow the same retention rules as other parse items, and because the path never touches the network, the clock, or a random seed, the JSON is safe to freeze in tests.