# Ohms Law vs Universal Security Instruments

The clearest difference is rating: Universal Security Instruments at 5.0 against Ohms Law's 4.3. Universal Security Instruments also leads on ads (none vs shown) and update cadence (every 2 months vs every 16 months). Ohms Law's advantage is ratings volume (7 vs 1) and iOS requirement (12.0 vs 14.0). On price, 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.

Universal Security Instruments holds the better App Store score, 5.0 against 4.3. That said, the two scores are not equally well evidenced: Ohms Law has 7 ratings behind it against 1, so its average is the more settled of the two.

Ohms Law ships an update every 16 months, Universal Security Instruments every 2 months. The most recent releases landed on October 23, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | Ohms Law | Universal Security Instruments |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.3 (7 ratings)](https://appshunter.io/ios/app/ohms-law/id590727537/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/universal-security-instruments/id6756246978/reviews)** |
| Number of ratings | **7** | 1 |
| Positive reviews | 70.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 16 months | **Every 2 months** |
| Monetization | Ad-supported | **Free** |
| Size | 12 MB | 200 MB |
| Requires iOS | **12.0** | 14.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Pro Certs Software Ltd](https://appshunter.io/developer/444429696) | [Feit Electric](https://appshunter.io/developer/1022520207) |

## What reviewers say

### Ohms Law

[App page](https://appshunter.io/ios/app/ohms-law/id590727537)

This utility app calculates voltage, current, resistance, and power using Ohm's Law. Simply input any two values, and the app will compute the remaining two, providing a comprehensive tool for electrical calculations.

**Highlights:** Calculate Voltage, Calculate Current, Calculate Resistance, Calculate Power, Input two values to find others

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

**In-app purchases:** none


### Universal Security Instruments

[App page](https://appshunter.io/ios/app/universal-security-instruments/id6756246978)

Manage and control your smart security and environmental devices remotely. This app offers a central hub for all your connected products, allowing for easy setup, monitoring, and sharing of device access with others.

**Highlights:** Remote device management, Monitor devices globally, Share device access, Simple and secure setup, Centralized hub for USI products

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Ohms Law free?

Ohms Law is free to download, with no in-app purchases.

### Is Universal Security Instruments free?

Universal Security Instruments is free to download, with no in-app purchases.

### Which has better reviews, Ohms Law or Universal Security Instruments?

Universal Security Instruments is rated higher. Ohms Law averages 4.3 out of 5 from 7 ratings, while Universal Security Instruments averages 5.0 from 1 ratings.

### Do Ohms Law or Universal Security Instruments have ads?

Ohms Law shows ads; Universal Security Instruments does not.

### Which is updated more often, Ohms Law or Universal Security Instruments?

Ohms Law ships an update every 16 months, and Universal Security Instruments every 2 months. Most recently, Ohms Law was updated on October 23, 2026 and Universal Security Instruments on October 16, 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.*