# 555 Timer & Oscillators Guide vs Electro Sim

The clearest difference is in-app purchases: 555 Timer & Oscillators Guide at none against Electro Sim's 2. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Electro Sim sells 2 one-off in-app purchases. 555 Timer & Oscillators Guide asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 4 months. The most recent releases landed on November 5, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 555 Timer & Oscillators Guide | Electro Sim |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (1 ratings)](https://appshunter.io/ios/app/electro-sim/id6758049588/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | Every 4 months |
| Monetization | — | Free with in-app purchases |
| Size | 20 MB | 19 MB |
| Requires iOS | **17.0** | 17.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [剑龙 刘](https://appshunter.io/developer/562718731) |

## What reviewers say

### 555 Timer & Oscillators Guide

[App page](https://appshunter.io/ios/app/555-timer-and-oscillators-guide/id6504487994)

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

**In-app purchases:** none


### Electro Sim

[App page](https://appshunter.io/ios/app/electro-sim/id6758049588)

Learn and teach basic electronics with an intuitive circuit simulator. Drag, wire, and combine components on a real-time canvas to visualize current flow and understand DC circuit concepts.

**Highlights:** Intuitive drag-and-drop canvas, Real-time DC simulation with current visualization, Extensive component library with search, Build and reuse custom components, Save, load, and export circuits, Undo/redo functionality

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $0.99 | one-time |
| Yearly | $3.99 | one-time |


## Frequently asked questions

### Is 555 Timer & Oscillators Guide free?

555 Timer & Oscillators Guide is free to download, with no in-app purchases.

### Is Electro Sim free?

Electro Sim is free to download, with in-app purchases available.

### Do 555 Timer & Oscillators Guide or Electro Sim have ads?

Neither 555 Timer & Oscillators Guide nor Electro Sim shows ads.

### Which is updated more often, 555 Timer & Oscillators Guide or Electro Sim?

555 Timer & Oscillators Guide ships an update every 4 months, and Electro Sim every 4 months. Most recently, 555 Timer & Oscillators Guide was updated on November 5, 2026 and Electro Sim 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.*