Opamp tools vs 555 Timer & Oscillators Guide
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Opamp tools
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This app is the collection of operational amplifier calculators. It is suitable for hobbyist or electronic engineer. Features * Inverting amplifier * Non-Inverting amplifier * Differential amplifier * Summing amplifier * Inverting comparator * First-order filter * Second-order filter (HPF) * Phase shift oscillator * Colpitts oscillator * Limit 5 combinations of component values * Share CSV via AirDrop * Upload CSV to iCloud Drive (For iOS8 or later) Pro Features * Instrumentation amplifier * Non-inverting comparator * Second-order filter (LPF) * Wien bridege oscillator * Hartley oscillator * No limitation of the number of suggestions * Selectable 1%,5%,10%,20% of values
555 Timer & Oscillators Guide
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Master the design of oscillators and waveform generators using 555 timer integrated circuits, digital logic integrated circuits, operational amplifiers, and transistors. The application provides a comprehensive collection of over 130 tutorials and circuit diagrams, covering 555 timer circuits and practical applications, CMOS 4000 series logic oscillators, TTL 74LS and 74HC series oscillators, operational amplifierβbased waveform generators, and transistor multivibrators. Designed for electronics beginners, students, hobbyists, and professional engineers, the app serves as a complete reference and learning tool for designing, understanding, and building oscillators, multivibrators, pulse generators, and waveform circuits commonly used in both analog and digital electronics. In addition to tutorials and schematics, the app includes built-in calculators for frequency, timing, duty cycle, and component value estimation, helping users quickly calculate and adjust circuit parameters. All topics are presented with clear circuit diagrams and detailed explanations. Available in 14 Languages: β’ English, French, German, Indonesian, Italian, Japanese, Polish, Portuguese, Russian, Simplified Chinese, Spanish, Turkish, Ukrainian, and Vietnamese β study in your native language! Covered Topics: β’ 555 Timer IC Series β’ Astable, monostable, and bistable modes β’ Pulse Width Modulation (PWM) β’ Voltage conversion circuits β’ Sensor and external module interfacing β’ CMOS Logic Oscillators β’ CMOS 4000 series circuits β’ Astable, monostable, and bistable modes β’ Gated CMOS oscillators β’ TTL / HC Logic Oscillators β’ TTL 74LS series circuits β’ 74HC series logic oscillators β’ Astable and monostable modes β’ Operational Amplifier Oscillators β’ Sine wave generators β’ Square-wave pulse generators β’ Triangle wave generators β’ Transistor-Based Oscillators β’ Transistor-Based Astable multivibrators β’ Transistor-Based Monostable multivibrators The content is regularly updated and expanded with each new release, ensuring the latest tutorials and circuit examples are always available.
Screenshots
Verdict
The clearest difference is in-app purchases: 555 Timer & Oscillators Guide at none against Opamp tools's 1. 555 Timer & Oscillators Guide also leads on update cadence (every 5 months vs every 12 months). Opamp tools's advantage is ads (none vs shown) and iOS requirement (12.0 vs 16.0). On price and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. Opamp tools sells 1 one-off in-app purchase. 555 Timer & Oscillators Guide asks for nothing beyond the download.
Opamp tools ships an update every 12 months, 555 Timer & Oscillators Guide every 5 months. The most recent releases landed on May 16, 2026 and September 24, 2026 respectively.
| Parameter | Opamp tools | 555 Timer & Oscillators Guide |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 12 months | Every 5 months β better |
| Ads | No β better | Yes |
| In-app purchases | Yes | No β better |
| Devices | iPhone, iPad, iPod β better | iPhone, iPad |
| Requires iOS | 12.0 β better | 16.0 |
| Further details β not scored | ||
| Size | 4 MB | 24 MB |
| Age rating | 4+ | +4 |
| Developer | Siu Yuen Ho | ALG Software Lab |
In-app purchases
Opamp tools
- Unlock pro feature$1.99
555 Timer & Oscillators Guide
No in-app purchases
Questions
Is Opamp tools free?
Is 555 Timer & Oscillators Guide free?
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