Operational Amplifiers Guide vs Alarm in Zone
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!
Alarm in Zone
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Set an alarm for a specific time in a specific city. It fires at that moment, no matter where you are in the world. **The problem** Standard alarms follow your device's current time zone. Cross a border and "7:00 AM" follows you to the new locale. That's fine, unless: - You're in Tokyo and want a reminder when it's 7:00 PM back home in Boston. - You're on a short trip and want to wake up on home time. - A launch or market open is scheduled at 10:30 AM Eastern and you want an alarm that stays anchored to Eastern, forever. Alarm in Zone gives each alarm its own location, and handles Daylight Savings Time and everything else automatically. The alarm fires at the right moment, always. **How it works** Tap +. Pick a time. Pick a city. Save. Each alarm shows its anchored time and zone, the next fire time in your current local time, and its repeat pattern. A subtle note appears when your device is in a different zone than one of your alarms — so you always know what fires and when. **What it is** One job: alarms anchored to a city. Free. No subscription, no ads, no accounts, no analytics. Requires iOS 26 or later.
Screenshots
Verdict
The clearest difference is ads: Alarm in Zone at none against Operational Amplifiers Guide's shown. Operational Amplifiers Guide's advantage is iOS requirement (16.0 vs 26.4). On price, update cadence, in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.
Operational Amplifiers Guide ships an update every 2 months, Alarm in Zone every 4 months. The most recent releases landed on October 1, 2026 and October 31, 2026 respectively.
| Parameter | Operational Amplifiers Guide | Alarm in Zone |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 2 months — better | Every 4 months |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 16.0 — better | 26.4 |
| Further details — not scored | ||
| Size | 17 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | ALG Software Lab | Apps From Outer Space, LLC |
In-app purchases
Operational Amplifiers Guide
No in-app purchases
Alarm in Zone
No in-app purchases
Questions
Is Operational Amplifiers Guide free?
Is Alarm in Zone free?
Do Operational Amplifiers Guide or Alarm in Zone have ads?
Which is updated more often, Operational Amplifiers Guide or Alarm in Zone?
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