Comparison

555 Timer & Oscillators Pro vs SewSkillz

Price, ratings, monetisation and update history for both apps, side by side β€” with what reviewers say about each.

Head to head
About

555 Timer & Oscillators Pro

Features
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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 amplifier–based 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 Pro edition provides additional tools for faster learning and easy navigation: β€’ Full-text search across all lessons and components β€’ Favorites for saving and organizing important topics The content is regularly updated and expanded with each new release, ensuring the latest tutorials and circuit examples are always available.

About

SewSkillz

Read full description

Sewskillz Class is a mobile learning application designed by Riohs College of Design to empower individuals with knowledge and skills to sew on their own. Offering a comprehensive library of video tutorials, the app provides step-by-step guidance for learners of all levels, from beginners to advanced seamstresses. With a focus on user-friendly functionality and high-quality content, RIOHS Sewskillz Class aims to revolutionize the way people learn and engage with sewing.

Screenshots

555 Timer & Oscillators Pro4 screens
SewSkillz3 screens

Verdict

The call

The clearest difference is price: SewSkillz at Free against 555 Timer & Oscillators Pro's $4.99. SewSkillz also leads on update cadence (every 3 weeks vs every 3 months). 555 Timer & Oscillators Pro's advantage is in-app purchases (none vs 8). On ads, device support and iOS requirement 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

CostPrice Β· In-app purchases Β· Ads Β· Monetization

SewSkillz is free to download; 555 Timer & Oscillators Pro costs $4.99 up front. SewSkillz sells 8 one-off in-app purchases. 555 Timer & Oscillators Pro asks for nothing beyond the download.

UpkeepUpdate frequency

555 Timer & Oscillators Pro ships an update every 3 months, SewSkillz every 3 weeks. The most recent releases landed on September 24, 2026 and June 20, 2026 respectively.

Scorecard3 real differences Β· 3 level
555 Timer & Oscillators Pro versus SewSkillz: the parameters behind the verdict, then further details
Parameter555 Timer & Oscillators ProSewSkillz
Price$4.99Free β€” better
Update frequencyEvery 3 monthsEvery 3 weeks β€” better
AdsNoNo
In-app purchasesNo β€” betterYes
DevicesiPhone, iPad, MaciPhone, iPad, iPod
Requires iOS16.015.1 β€” better
Further details β€” not scored
Size22 MB37 MB
Age rating4+12+
DeveloperALG Software LabRiohs Originate

In-app purchases

None

555 Timer & Oscillators Pro

No in-app purchases

8 purchases

SewSkillz

One-time8
  • Monthly Access$9.99
  • Style Surge$9.99
  • Designer's Deluxe$29.99
Show 5 more
  • Trendsetter$29.99
  • Creative Saver$49.99
  • Fashion Flash$49.99
  • Style Surge$99.99
  • Designer’s Deluxe$99.99

Questions

Is 555 Timer & Oscillators Pro free?
555 Timer & Oscillators Pro costs $4.99, with no in-app purchases.
Is SewSkillz free?
SewSkillz is free to download, with in-app purchases available.
Do 555 Timer & Oscillators Pro or SewSkillz have ads?
Neither 555 Timer & Oscillators Pro nor SewSkillz shows ads.
Which is updated more often, 555 Timer & Oscillators Pro or SewSkillz?
555 Timer & Oscillators Pro ships an update every 3 months, and SewSkillz every 3 weeks. Most recently, 555 Timer & Oscillators Pro was updated on September 24, 2026 and SewSkillz on June 20, 2026.

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