Timer 555 Calculator vs LED System
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Timer 555 Calculator
Calculate monostable and astable circuits for electronics projects. Determine pulse width and frequency, find component combinations, and save/upload data. Supports multiple languages.
- Monostable circuit pulse width calculation
- Astable circuit frequency calculation
- Component combination finder
- Save component values to CSV
- Upload CSV via AirDrop/iCloud Drive
- Multi-language support
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This app is used to calculate monostable and astable circuit. Features * Calculate pulse width of monostable circuit * Calculate frequency of astable circuit * Find out combination of components making a desire pulse width in monostable circuit * Find out combination of components making a desire frequency in astable circuit * Saving component values in CSV file * Upload generated CSV files via AirDrop or iCloud Drive * Support English, German, French, Italian, Spanish, Portuguese, Japanese, Korean, Russian
LED System
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这是一个用来管理LED价格牌的APP，用户通过这个应用可以集中管理分布于各地的价格牌。价格牌被分组管理。用户可以查询和设置价格牌的显示数值，也可以查询和设置价格牌的亮度。每个价格牌最多可显示12行价格信息，每行可轮流显示现金价格和信用卡价格。 用户需要有权限才能操作，用户操作权限分为4级： 1. 超级管理员：整个系统的最高管理者，管理超级操作员和一般管理员。 2. 超级操作员：由超级管用员创建，可以查看系统中所有的价格牌信息，但是没有设置权限。 3. 一般管理员：由超级管用员创建，可以增删分组，增删价格牌，增删一般操作员，给一般操作员分配对分组的权限。 4. 一般操作员：由一般管理员创建，具体权限由创建他的一般管理员分配，可以拥有对分组的如下权限：查看分组价格牌、编辑分组价格牌、设置分组价格牌显示的价格、升级价格牌固件。
Screenshots
Verdict
The clearest difference is in-app purchases: LED System at none against Timer 555 Calculator's 1. LED System also leads on update cadence (weekly vs every 3 months). Timer 555 Calculator's advantage is iOS requirement (13.2 vs 15). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Timer 555 Calculator sells 1 one-off in-app purchase. LED System asks for nothing beyond the download.
Timer 555 Calculator ships an update every 3 months, LED System weekly. The most recent releases landed on September 24, 2026 and September 15, 2026 respectively.
| Parameter | Timer 555 Calculator | LED System |
|---|---|---|
| Price | Free | Free |
| Rating | 3.9 (8 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 8 — better | — |
| Update frequency | Every 3 months | Weekly — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 13.2 — better | 15 |
| Further details — not scored | ||
| Size | 3 MB | 64 MB |
| Age rating | 4+ | 17+ |
| Developer | Siu Yuen Ho | 深圳市流明电子有限公司 |
In-app purchases
Timer 555 Calculator
- Unlock Pro feature$0.99
LED System
No in-app purchases
Questions
Is Timer 555 Calculator free?
Is LED System free?
Do Timer 555 Calculator or LED System have ads?
Which is updated more often, Timer 555 Calculator or LED System?
Other comparisons
