# Resistor Tools Pro vs Operational Amplifiers Guide

The clearest difference is price: Operational Amplifiers Guide at Free against Resistor Tools Pro's $0.99. Resistor Tools Pro's advantage is ads (none vs shown) and iOS requirement (12.0 vs 16.0). On update cadence, in-app purchases and device support there is nothing between them.

Operational Amplifiers Guide is free to download; Resistor Tools Pro costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on June 25, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Resistor Tools Pro | Operational Amplifiers Guide |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/resistor-tools-pro/id825620924/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | Paid | — |
| Size | 4 MB | 17 MB |
| Requires iOS | **12.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Siu Yuen Ho](https://appshunter.io/developer/814088527) | [ALG Software Lab](https://appshunter.io/developer/1650561236) |

## What reviewers say

### Resistor Tools Pro

[App page](https://appshunter.io/ios/app/resistor-tools-pro/id825620924)

This utility app offers a suite of tools for calculating and finding resistor combinations. It's designed for electronics enthusiasts and professionals needing to determine series, parallel, and voltage divider configurations. Save and share your calculations easily.

**Highlights:** Calculate series/parallel resistance, Find resistor combinations for desired resistance, Voltage divider ratio and value calculation, Inverting amplifier gain calculation, Save combinations to CSV, Share via AirDrop, Upload CSV to iCloud Drive

**In-app purchases:** none


### Operational Amplifiers Guide

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

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

**In-app purchases:** none


## Frequently asked questions

### Is Resistor Tools Pro free?

Resistor Tools Pro costs $0.99, with no in-app purchases.

### Is Operational Amplifiers Guide free?

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

### Do Resistor Tools Pro or Operational Amplifiers Guide have ads?

Operational Amplifiers Guide shows ads; Resistor Tools Pro does not.

### Which is updated more often, Resistor Tools Pro or Operational Amplifiers Guide?

Resistor Tools Pro ships an update every 2 months, and Operational Amplifiers Guide every 2 months. Most recently, Resistor Tools Pro was updated on June 25, 2026 and Operational Amplifiers Guide on September 19, 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.*