# Operational Amplifiers Guide vs QR Previewer

The clearest difference is ads: QR Previewer at none against Operational Amplifiers Guide's shown. On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

## The numbers

| Metric | Operational Amplifiers Guide | QR Previewer |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | — |
| Size | 17 MB | 5 MB |
| Requires iOS | **16.0** | 17.0 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Lee Hyojoong](https://appshunter.io/developer/1888028738) |

## What reviewers say

### Operational Amplifiers Guide

[App page](https://appshunter.io/ios/app/operational-amplifiers-guide/id6467499897)

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

**In-app purchases:** none


### QR Previewer

[App page](https://appshunter.io/ios/app/qr-previewer/id6762736386)

**In-app purchases:** none


## Frequently asked questions

### Is Operational Amplifiers Guide free?

Operational Amplifiers Guide is free to download, with no in-app purchases.

### Is QR Previewer free?

QR Previewer is free to download, with no in-app purchases.

### Do Operational Amplifiers Guide or QR Previewer have ads?

Operational Amplifiers Guide shows ads; QR Previewer does not.

---

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