# Operational Amplifiers Guide vs Alarm in Zone

The clearest difference is ads: Alarm in Zone at none against Operational Amplifiers Guide's shown. Operational Amplifiers Guide's advantage is iOS requirement (16.0 vs 26.4). On price, update cadence, in-app purchases and device support there is nothing between them.

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

Operational Amplifiers Guide ships an update every 2 months, Alarm in Zone every 4 months. The most recent releases landed on October 1, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Operational Amplifiers Guide | Alarm in Zone |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Every 2 months** | Every 4 months |
| Size | 17 MB | 6 MB |
| Requires iOS | **16.0** | 26.4 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Apps From Outer Space, LLC](https://appshunter.io/developer/673290835) |

## 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


### Alarm in Zone

[App page](https://appshunter.io/ios/app/alarm-in-zone/id6774044742)

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

**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 Alarm in Zone free?

Alarm in Zone is free to download, with no in-app purchases.

### Do Operational Amplifiers Guide or Alarm in Zone have ads?

Operational Amplifiers Guide shows ads; Alarm in Zone does not.

### Which is updated more often, Operational Amplifiers Guide or Alarm in Zone?

Operational Amplifiers Guide ships an update every 2 months, and Alarm in Zone every 4 months. Most recently, Operational Amplifiers Guide was updated on October 1, 2026 and Alarm in Zone on October 31, 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.*