Comparison

Operational Amplifiers Guide vs QR Previewer

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

Head to head
About

Operational Amplifiers Guide

Features
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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!

About

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.

Screenshots

Operational Amplifiers Guide4 screens
QR Previewer4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Scorecard1 real difference · 5 level
Operational Amplifiers Guide versus QR Previewer: the parameters behind the verdict, then further details
ParameterOperational Amplifiers GuideQR Previewer
PriceFreeFree
Update frequencyEvery 2 months—
AdsYesNo — better
In-app purchasesNoNo
DevicesiPhone, iPad — betteriPhone
Requires iOS16.0 — better17.0
Further details — not scored
Size17 MB5 MB
Age rating4+4+
DeveloperALG Software LabLee Hyojoong

In-app purchases

None

Operational Amplifiers Guide

No in-app purchases

None

QR Previewer

No in-app purchases

Questions

Is Operational Amplifiers Guide free?
Operational Amplifiers Guide is free to download, with no in-app purchases.
Is QR Previewer free?
QR Previewer is free to download, with no in-app purchases.
Do Operational Amplifiers Guide or QR Previewer have ads?
Operational Amplifiers Guide shows ads; QR Previewer does not.

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