# Harmonic Wave Equation Calc vs PID Controller Simulation

The clearest difference is rating: Harmonic Wave Equation Calc at 5.0 against PID Controller Simulation's 3.0. Harmonic Wave Equation Calc also leads on price ($2.99 vs $3.99). PID Controller Simulation's advantage is update cadence (every 3 months vs every 31 months). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

Harmonic Wave Equation Calc costs $2.99 and PID Controller Simulation $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Harmonic Wave Equation Calc holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

Harmonic Wave Equation Calc ships an update every 31 months, PID Controller Simulation every 3 months. The most recent releases landed on July 6, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | Harmonic Wave Equation Calc | PID Controller Simulation |
| --- | --- | --- |
| Price | **$2.99** | $3.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/harmonic-wave-equation-calc/id1412323951/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/pid-controller-simulation/id6612009107/reviews) |
| Number of ratings | 1 | **2** |
| Positive reviews | — | 33.3% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 31 months | **Every 3 months** |
| Monetization | Paid | Paid |
| Size | 1 MB | 6 MB |
| Requires iOS | 13 | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Tan Chia Ling](https://appshunter.io/developer/321121189) | [立娜 王](https://appshunter.io/developer/1761096632) |

## What reviewers say

### Harmonic Wave Equation Calc

[App page](https://appshunter.io/ios/app/harmonic-wave-equation-calc/id1412323951)

This physics and math calculator quickly determines wave properties like displacement, velocity, and amplitude. It provides instant calculations with copyable results and includes reference formulas. Optimized for everyday use, it supports high precision and various units.

**Highlights:** Instant wave calculations, Copyable results, Included reference formulas, Supports 16 decimal places, Multiple unit support, Ad-free and private

**Features:** macOS Compatibility

**In-app purchases:** none


### PID Controller Simulation

[App page](https://appshunter.io/ios/app/pid-controller-simulation/id6612009107)

Master PID control theory and practice with this comprehensive simulation platform. Learn fundamental concepts, tune parameters, and simulate real-world applications like temperature and motor speed control. Export PID parameters as production-ready code in multiple languages.

**Highlights:** Comprehensive tutorial system, Interactive scenario simulations, Performance analysis tools, Code generator for multiple languages, Real-time curve visualization, Advanced PID algorithm explanations

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Harmonic Wave Equation Calc free?

Harmonic Wave Equation Calc costs $2.99, with no in-app purchases.

### Is PID Controller Simulation free?

PID Controller Simulation costs $3.99, with no in-app purchases.

### Which has better reviews, Harmonic Wave Equation Calc or PID Controller Simulation?

Harmonic Wave Equation Calc is rated higher. Harmonic Wave Equation Calc averages 5.0 out of 5 from 1 ratings, while PID Controller Simulation averages 3.0 from 2 ratings.

### Do Harmonic Wave Equation Calc or PID Controller Simulation have ads?

Neither Harmonic Wave Equation Calc nor PID Controller Simulation shows ads.

### Which is updated more often, Harmonic Wave Equation Calc or PID Controller Simulation?

Harmonic Wave Equation Calc ships an update every 31 months, and PID Controller Simulation every 3 months. Most recently, Harmonic Wave Equation Calc was updated on July 6, 2026 and PID Controller Simulation on September 23, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*