# 555 Timer & Oscillators Guide vs electronics filter toolkit

The clearest difference is in-app purchases: 555 Timer & Oscillators Guide at none against electronics filter toolkit's 1. electronics filter toolkit's advantage is iOS requirement (13.0 vs 16.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. electronics filter toolkit sells 1 one-off in-app purchase. 555 Timer & Oscillators Guide asks for nothing beyond the download.

555 Timer & Oscillators Guide ships an update every 5 months, electronics filter toolkit every 9 months. The most recent releases landed on September 24, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | 555 Timer & Oscillators Guide | electronics filter toolkit |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 5 months** | Every 9 months |
| Monetization | — | Free with in-app purchases |
| Size | 24 MB | 29 MB |
| Requires iOS | 16.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | +4 | 4+ |
| Developer | [ALG Software Lab](https://appshunter.io/developer/1650561236) | [Anas Abubakar](https://appshunter.io/developer/1581534101) |

## 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


### electronics filter toolkit

[App page](https://appshunter.io/ios/app/electronics-filter-toolkit/id6754560517)

Design various types of electronic filters, including RC, RL, RLC, and passive crossovers, with customizable orders and alignments. Instantly obtain component values and Bode insights for lab, classroom, or audio projects. Ideal for engineers, hobbyists, and students.

**Highlights:** Design RC, RL, and RLC filters (2nd-7th order), Butterworth & Chebyshev alignments, Passive crossover calculations, Twin-T notch filter design, Instant component values, Bode insights, Offline-friendly dark mode UI

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Upgrade to Pro | $2.99 | 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 electronics filter toolkit free?

electronics filter toolkit is free to download, with in-app purchases available.

### Do 555 Timer & Oscillators Guide or electronics filter toolkit have ads?

Both 555 Timer & Oscillators Guide and electronics filter toolkit show ads.

### Which is updated more often, 555 Timer & Oscillators Guide or electronics filter toolkit?

555 Timer & Oscillators Guide ships an update every 5 months, and electronics filter toolkit every 9 months. Most recently, 555 Timer & Oscillators Guide was updated on September 24, 2026 and electronics filter toolkit on September 9, 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.*