# 555 Timer Calculator — Astable & Monostable Designer

> Astable & Monostable Designer (iPhone/iPad app by Nitrio.)

- Source: https://appshunter.io/ios/app/555-timer-calculator/id6770780910 (this page in markdown: same URL + `.md`)
- Developer: [Nitrio](https://appshunter.io/developer/321121189)
- Category: Utilities, Productivity
- Price: $3.99
- Age rating: 4+
- Requires: iOS 17.6 · 0 MB
- Languages: American English
- Released: 2026-05-20
- Data updated: 2026-08-17
- User reviews in markdown: https://appshunter.io/ios/app/555-timer-calculator/id6770780910/reviews.md

## What is 555 Timer Calculator?

Design, simulate, and learn the legendary NE555 timer chip — right on your iPhone or iPad. Whether you’re a hobbyist building your first LED blinker or an engineer prototyping a PWM driver, 555 Timer Calculator delivers instant, textbook-accurate results with a live oscilloscope waveform you can watch in real time.

KEY FEATURES
• Astable (Oscillator) Mode
Compute frequency, period, duty cycle, Ton and Toff from R1, R2 and C. The square wave animates on a retro green-phosphor oscilloscope so you see exactly what your circuit will output.

• Monostable (One-Shot) Mode
Get precise pulse width T = 1.1 × R × C for time delays, switch debouncers and trigger circuits. Watch the trigger and output pulses animate side by side.

• Interactive Inputs
Drag the sliders or tap to type values directly. Full unit support — Ω, kΩ, MΩ and pF, nF, μF. 

• Live Waveform & Duty Cycle Ring
Animated oscilloscope with pinch-style zoom plus a colour-coded duty cycle ring let you spot timing problems at a glance.

• Ready-Made Preset Circuits
Tap a preset to load proven designs: 1 Hz LED blinker, 1 kHz audio tone, 10 ms debounce pulse, 100 ms delay, 50 % square wave and 75 % PWM for motors.

• Built-In 555 Reference
A complete in-app guide explains how the 555 works internally, every pin (VCC, GND, TRG, OUT, RST, CTL, THR, DIS), all formulas, common uses and practical design tips for stable, accurate timing.

WHO IT’S FOR
Electronics students, makers building Arduino and Raspberry Pi peripherals, EE professionals prototyping clocks and PWM drivers, ham radio operators, robotics enthusiasts and anyone who has ever reached for a breadboard.

WHY 555 TIMER CALCULATOR
No internet required. No accounts. No subscriptions. No ads. Just a fast, precise, beautifully designed engineering tool with a dark-mode oscilloscope aesthetic. Every formula matches the standard datasheets used by Texas Instruments, NXP and ON Semiconductor.

Thanks for your support and visit nitrio.com for more apps for your iOS devices.

## Chart rankings

- #194 in Top Paid · Utilities (US App Store)


## Version history (last 1 release)

### 1.0 — 2026-05-20

No release notes.

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All apps by Nitrio: https://appshunter.io/developer/321121189

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-17.*