Operational Amplifiers Guide vs QR Previewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Operational Amplifiers Guide
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Operational Amplifiers Guide is your essential tool for designing and analyzing circuits using op-amps and comparators. Whether you're a student, electronics enthusiast, or experienced engineer, this app helps you create, calculate, and understand a wide variety of op-amp–based circuits with ease. Use it as a practical reference when developing projects, building prototypes, or studying amplifier configurations. The app also includes technical data on popular operational amplifier and comparator series — making it a handy guide for both design and selection. Available in 14 Languages: • English, French, German, Indonesian, Italian, Japanese, Polish, Portuguese, Russian, Simplified Chinese, Spanish, Turkish, Ukrainian, and Vietnamese — study in your native language! Key Features: • Interactive calculators for common op-amp circuits • Step-by-step explanations and formulas • Reference info on op-amps and comparators • Ideal for learning, prototyping, or quick checks • Light and dark mode support The application contains the following guides and calculators: Amplifiers • Non-inverting operational amplifier • Inverting operational amplifier • Inverting amplifier with T-bridge in OS • Differential amplifier • Differential amplifier with T-bridge in OS • Voltage repeater • Inverting voltage repeater • AC voltage amplifier • High Input Impedance AC Voltage Amplifier • AC voltage repeater ActiveFilters • Non-inverting low-pass filter • Inverting low-pass filter • Non-inverting high-pass filter • Inverting high pass filter • Bandpass filter • Gyrator Integrators and differentiators • Voltage integrator • Sum integrator • Integrator with signal amplification • Difference integrator • Double integrator • Voltage differentiator • Sum Differentiator • Differentiator with T-bridge • Differentiator with T-bridge made of capacitors • Difference differentiator Comparators • Comparator • Limiter • Limiter with zener diode at the input • RS trigger Attenuators • Non-inverting attenuator • Inverting attenuator Converters • Voltage-to-current converter with non-inverting input • Voltage to current converter with inverting input • Voltage to current converter with differential input Adders and substactors • Inverting adder • Addition-subtraction circuit • Non-inverting adder Logarithmic and exponential amplifiers • Diode-based logarithmic amplifier • Transistor-based logarithmic amplifier • Diode exponential amplifier • Exponential transistor amplifier Sine Wave generators: • Op-Amp Oscillators • Oscillator with Diode in the Feedback Path • Twin-T Network Signal Generator Square-wave pulse generators • Op-Amp Square-Wave Generator • Adjustable Square-Wave Generator • Enhanced Square-Wave Generator • Duty-Cycle Adjustment Triangle-wave signal generators • Nonlinear Triangle-Wave Generator • Variable-Symmetry Sawtooth Generator • Linear Triangle-Wave Generator • Adjustable Linear Triangle-Wave Generator • Variable-Symmetry Ramp Generator Popular operational amplifiers: description and pinout Popular comparators: description and pinout Download now and power up your electronics work!
QR Previewer
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**QR Previewer** helps you check a QR destination before you open it. Instead of launching a website immediately, QR Previewer shows where the QR code leads first, so you can decide what to do next. **Features** * Preview the destination before opening * View a readable URL and domain details * Review local risk signals such as HTTP links, short links, IP-based hosts, and heavy tracking parameters * Get a cleaner link suggestion when removable tracking parameters are detected * Choose how to continue: open in Safari, use the in-app browser, or copy the link * Revisit your most recent scans on this device **Why use QR Previewer** QR menus, event links, and shared codes often open too quickly. QR Previewer adds a simple review step, making it easier to inspect unfamiliar destinations before visiting them. **Important** QR Previewer provides local heuristic guidance only. It does not guarantee safety and is not a malware scanner or phishing blocker. **Privacy** Scan results are processed on device in the current version. QR Previewer itself does not upload your scanned URLs or scan history.
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Verdict
The clearest difference is ads: QR Previewer at none against Operational Amplifiers Guide's shown. On price, in-app purchases, device support and iOS requirement 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. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Operational Amplifiers Guide | QR Previewer |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 2 months | — |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 16.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 17 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | ALG Software Lab | Lee Hyojoong |
In-app purchases
Operational Amplifiers Guide
No in-app purchases
QR Previewer
No in-app purchases
Questions
Is Operational Amplifiers Guide free?
Is QR Previewer free?
Do Operational Amplifiers Guide or QR Previewer have ads?
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