# 555 Timer & Oscillators Pro vs Learning transistor

The clearest difference is price: Learning transistor at Free against 555 Timer & Oscillators Pro's $4.99. 555 Timer & Oscillators Pro's advantage is in-app purchases (none vs 1) and chart position (#193 vs unranked). On ads and iOS requirement there is nothing between them.

Learning transistor is free to download; 555 Timer & Oscillators Pro costs $4.99 up front. Learning transistor sells 1 one-off in-app purchase. 555 Timer & Oscillators Pro asks for nothing beyond the download.

## The numbers

| Metric | 555 Timer & Oscillators Pro | Learning transistor |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | — |
| Best chart rank | **#193** | — |
| Size | 22 MB | 1 MB |
| Requires iOS | **16.0** | 17.0 |
| Devices | **iPhone, iPad, Mac** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Sungjun Kim](https://appshunter.io/developer/1602461985) |

## What reviewers say

### 555 Timer & Oscillators Pro

[App page](https://appshunter.io/ios/app/555-timer-and-oscillators-pro/id6504415162)

**Currently charting:** #193 Top Paid · Education (US App Store)

**Features:** Vision Pro support

**In-app purchases:** none


### Learning transistor

[App page](https://appshunter.io/ios/app/learning-transistor/id6792466363)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access | $4.99 | one-time |


## Frequently asked questions

### Is 555 Timer & Oscillators Pro free?

555 Timer & Oscillators Pro costs $4.99, with no in-app purchases.

### Is Learning transistor free?

Learning transistor is free to download, with in-app purchases available.

### Do 555 Timer & Oscillators Pro or Learning transistor have ads?

Neither 555 Timer & Oscillators Pro nor Learning transistor shows ads.

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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.*