# Bode & Nyquist

> Tool for plotting Bode and Nyquist diagrams of transfer functions and evaluating system stability. (iPhone/iPad app by Fabrizio Boco.)

- Source: https://appshunter.io/ios/app/bode-and-nyquist/id445573307 (this page in markdown: same URL + `.md`)
- Developer: [Fabrizio Boco](https://appshunter.io/developer/466239616)
- Category: Productivity, Education
- Price: $5.99
- Age rating: 4+
- Requires: iOS 16.6 · 1 MB
- Languages: American English, Italian
- Released: 2011-06-28
- Data updated: 2026-08-23
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/bode-and-nyquist/id445573307/reviews.md

## What is Bode & Nyquist?

This application allows you to plot the Bode and Nyquist diagrams of a transfer function and visualize its impulse response, providing tools to analyze both frequency-domain behavior and time-domain dynamics.

The transfer function is entered via a simple numeric keypad and has been specially adapted to make immediately available all the keys you need.

Open Loop Transfer function or the Closed Loop Transfer can be entered separately.

The app automatically evaluate system stability.

The number of unstable closed-loop poles, the number of unstable open-loop poles and the number of clock-wise encirclements of point -1+j0 are shown together with the Nyquist Plot.

Gain and Phase margin are shown together with the Bode Plot.

For each graph the following gestures are supported:

* Drag: To move the chart in the desired position;
* Pinch: To enlarge or shrinks the graph;
* Double Tap to restore the position and zoom level of the graph to their original values​​.

Through a dedicated function you can set the maximum frequency of the Nyquist diagram and the frequency range for the Bode diagrams of the module and phase.

There is also a complete online help.

BEFORE LEAVING AN ANONYMOUS NEGATIVE FEEDBACK AND THROW AWAY YOUR MONEY:

1) READ THE MANUAL AGAIN;

2) CHECK AGAIN THE SYNTAX OF THE ENTERED FUNCTION;

3) CONTACT ME, AND I WILL DO MY VERY BEST TO HELP YOU.

A promo code for my Circuit Lab app will be send to users who will be able to report a recognized bug of this application.

## Key features

- Plot Bode and Nyquist diagrams
- Evaluate system stability
- Display gain and phase margins
- Show encirclements of -1+j0
- Interactive graph gestures (drag, pinch, double tap)
- Adjust frequency ranges
- Integrated online help

## Recent user reviews (5 of 5)

All indexed reviews: https://appshunter.io/ios/app/bode-and-nyquist/id445573307/reviews.md

### 1/5 — Horrible

*2018-07-23*

Is the worst app that I have payed in my life, I WANT BACK MY MONEY

### 1/5 — terrible

*2013-06-03*

worst 6 $ ever spent !! 
u cheaters !!!!

### 2/5 — Kann die Grundfunktionen aber nicht mehr

*2012-10-11*

Also man kann einfache Funktionen darstellen lassen, jedoch hat das Programm schon Probleme wenn es um die Darstellung geht, der Plot ist extrem langsam und Störanfällig. Auch stellt das Programm keine zusammengesetzten Funktionen dar. 
Es kann nicht einmal Totzeitglieder darstellen, aber auch nichts anderes was mit der e-Funktion zu tuen hat. 
Bitte Bitte Bitte noch Funktionen einfügen. Nyquist Kriterium kann man auch die entsprechenden Hilfen anzeigen. Im Bodediagramm könnte man auch noch Knickfrequenz und Schnittfrequenz einfügen.

Alles in allem kann das Programm nicht viel und das noch nicht mal sonderlich gut. Aber trotzdem Zwei Sterne weil es das erste war. Ansonsten kann man auch zu Wolfram Alpha greifen, da bekommt man noch die beste Tastatur im gesamten AppStore.

### 5/5 — Sehr hilfreich

*2012-06-25*

Sehr hilfreich, um sich den Verlauf von bodediagrammen vorstellen zu können, wenn man matlab gerade nicht zur Hand hat.

### 2/5 — Nice but buggy

*2012-05-10*

Seems to work but there are a number of bugs and annoying things.
1. the frequency settings should stay the same or auto scale. Every time you reselect it, it goes back to the default. Very annoying.
2. Flipping through Bode to Nyquist back to Bode, the output changes to an incorrect transfer function
3. Why don't phase and magnitude appear on the same screen. This is traditional. You need to flip back and forth. Annoying.
4. Doesn't understand exponential notation. You need to use 10^n 
5. Why only transfer function.  Why cant it be a poles zeroes option to eliminate typing.

This app could be great if it were modified only slightly to create a more practical tool. At the present state worth $2.99 not $5.99.

## Frequently asked questions about Bode & Nyquist

### What is Bode & Nyquist used for?

Bode & Nyquist is used to plot Bode and Nyquist diagrams for transfer functions, helping users analyze system stability. It automatically calculates and displays important metrics like gain margin, phase margin, and encirclements of the critical point.

### How does Bode & Nyquist evaluate system stability?

The application evaluates system stability by analyzing the Bode and Nyquist plots. It shows the number of unstable closed-loop poles, unstable open-loop poles, and the number of clockwise encirclements of the point -1+j0, providing a comprehensive stability assessment.

### What are the interactive features for the graphs in Bode & Nyquist?

Bode & Nyquist supports several gestures for graph interaction: drag to move the chart, pinch to zoom in or out, and double-tap to restore the graph to its original position and zoom level.

### Can I customize the frequency ranges in Bode & Nyquist?

Yes, Bode & Nyquist allows you to set the maximum frequency for the Nyquist diagram and the frequency range for both the module and phase Bode diagrams through a dedicated function.

### Is there a help guide available for Bode & Nyquist?

Yes, Bode & Nyquist includes a complete online help section accessible within the application. It is recommended to consult the manual before reporting issues.

### What devices is Bode & Nyquist compatible with?

Bode & Nyquist is available for iPhone, iPad, and iPod devices. It requires iOS 4.3 or later.

### How often is Bode & Nyquist updated?

The latest version of Bode & Nyquist is 3.0, last updated on April 18, 2023. Updates typically address bugs and improve functionality.

### What is the price of Bode & Nyquist?

Bode & Nyquist is a paid application priced at $5.99. There are no in-app purchases or advertisements.

## Version history (last 5 releases)

### 3.3.0 — 2026-08-05

- Added impulse response analysis.
- Added open-loop and closed-loop Bode plots when both G(s) and H(s) are provided.
- Updated documentation.
- Minor fixes and performance improvements.

### 3.2.0 — 2026-06-11

Fixes to work with iOS 26.5.1.
Performance improvements.

### 3.0 — 2023-04-18

User interface redesigned
Open Loop Transfer function and Closed Loop Transfer function can be entered separately
The app automatically evaluate system stability, number of unstable closed loop poles, number of unstable open-loop poles and number of clock-wise encirclements about -1+j0 are provided together with the Nyquist Plot
Gain and Phase Margin are provided together with the Bode Plot
Cursor on Nyquist Plot to show real and imaginary part of the transfer function along the plot
Cursor on Bode Plot to show Gain and Phase along the plot

### 2.1 — 2020-02-04

Bug fixing

### 2.0 — 2019-10-21

The user interface has been redesigned
Open Loop Transfer function or the Closed Loop Transfer can be entered separately 
The app automatically evaluate system stability
The number of unstable closed-loop poles, the number of unstable open-loop poles and the number of clock-wise encirclements of point -1+j0 are shown together with the Nyquist Plot
Gain and Phase margin are shown together with the Bode Plot

## More apps by Fabrizio Boco

- [Matrix Lab](https://appshunter.io/ios/app/matrix-lab/id337754158)
- [DCircuit Lab](https://appshunter.io/ios/app/dcircuit-lab/id382544208)
- [DCircuit Lab HD](https://appshunter.io/ios/app/dcircuit-lab-hd/id392966166)
- [Arduino Manager](https://appshunter.io/ios/app/arduino-manager/id497240094)
- [Logic Analyzer](https://appshunter.io/ios/app/logic-analyzer/id980880317)

All apps by Fabrizio Boco: https://appshunter.io/developer/466239616

## Related topics

[bode plot](https://appshunter.io/ios/topics/bode-plot)

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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 2026-08-23.*