555 Timer Calculator API
555-timer (NE555) astable and monostable design as an API, computed locally and deterministically. The astable endpoint designs the classic oscillator: from the two timing resistors R1 and R2 and the capacitor it returns the output frequency f = 1/(ln2·(R1+2R2)·C), the high and low times (T_high = ln2·(R1+R2)·C, T_low = ln2·R2·C), the period and the duty cycle (R1+R2)/(R1+2R2), or solves the capacitor for a target frequency. The monostable endpoint designs the one-shot timer, T = 1.1·R·C — the pulse width of a single output pulse — and solves for whichever of the resistance, capacitance or pulse width you leave out. The design endpoint works backwards: from a target frequency, a chosen capacitor and a duty cycle it computes the resistor values R1 and R2 you need (a standard 555 needs a duty above 50 %). Capacitors may be entered in farads, microfarads, nanofarads or picofarads. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics-hobbyist and maker tools, oscillator, blinker, PWM and timing-circuit design, and electronics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is 555-timer design; for Ohm's law, reactance and RC time constants use an Ohm's-law API.
api.oanor.com/timer555-api
