Comparison

RPN vs Operational Amplifiers Pro

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

Head to head
About

RPN

This app simulates a legendary 1970s programmable calculator, offering advanced features for scientists and engineers. It allows users to run programs, manage virtual cards, and access hundreds of free program cards from its website.

Highlights
  • Virtual program and data cards
  • Virtual paper tape printer
  • Database-driven card manager
  • Create, label, and organize unlimited cards
  • Effortless saving of card collections
  • Formatted program listings
  • Live display of stack and registers
Features
Read full description

A dream calculator of the 70's, priced at $3,200 in today's dollars, now affordable for everyone! RPN-97 Pro is the first complete simulation of Hewlett-Packard's legendary HP-97 programmable calculator for iOS. Produced from 1976 to 1984, the HP-97's features coupled with its capability to store programs on magnetic cards made it a huge success among scientists, engineers and other professionals. Thousands of programs were written for it. Now you can run them right on your iPad, with more ease and faster than ever before. To get you started quickly, download hundreds of program cards from our website for free. What users said: “The most delightful app I possess. The magnet card reader emulation rocks. Would have paid much more for this." "As the owner of an actual working HP 97 calculator, I am blown away with this new simulator. Simply fabulous." "Whoever coded this my hat goes off to you - what a professional piece of work, incredible app." RPN-97 Pro is fully compatible with RPN-67 Pro, its companion simulator of the HP-67 calculator. Features: • Virtual program and data cards • Virtual paper tape printer • Powerful database-driven card manager • Create, label, and organize a virtually unlimited number of cards • Use iTunes to effortlessly save entire card collections on your Mac/PC • Sharing: e-mail, AirDrop, Dropbox, copy, paste, print • Formatted listing clearly showing labels and targets of branches • E-mail listings and let the recipient paste the text right into RPN-97 • Print listings on any AirPrint-compatible printer • Program listing on paper tape shows subroutine nesting • Edit paper tape • E-mail paper tape, or print it via AirPrint • Cut/copy/paste displayed value or program steps • Paste HP-67 or HP-97 listings from other sources into RPN-97 and run them • "Live" display of stack, memory registers, program counter, flags • Show program usage notes • 30 selectable background images, even add your own • Much faster than a real HP-97 • Low-battery indicator (iPad charge 10% or less) • Compatible with RPN-67 Pro and RPN-67 SD, CuVee Software's HP-67 simulators • Supports hardware keyboard While RPN-97 Pro can work exactly like a real HP-97, changing a simple setting will turn the app into a super-charged HP-97: • Up to 999 program steps, 8 subroutine levels, 6 additional flags (F4...F9) • 100 additional registers • 100 additional labels • 100 built-in constants and conversions • More than 150 additional powerful operations and functions Plus: • 15 commands to print and manipulate any range of extended registers • Unrestricted register arithmetic • Exchange x with any register • Complex numbers mode, hyperbolic functions • Non-volatile memory - stack, registers, program, flags, paper tape • Status indicators for prefix keys (EXT, f, LBL, GTO, etc.) • Display showing thousands separators (optional) • Text output on paper tape in 10 colors, even simple plotting • Stack-of-stack: push/pop the entire stack on internal stack (4 levels) • Single-step into subroutines (optional) • Powerful debugging aids, including 10 breakpoints with counters • Keycodes translated to command name while entering or single-stepping a program • Change the duration of the PAUSE command • Cancel SST or BST operation by simply sliding your finger off the depressed key • Compress constants in programs into a single step (reversible) • Use existing programs in text format by a simple paste operation RPN-97 Pro comes with more than 130 programs pre-installed, including HP Standard Pac, HP Business Decisions Pac, HP Math Pac I, HP Stat Pac I, and HP Surveying Pac I. The simulator has been verified to correctly run the examples given in HP Civil Engineering Pac I, HP Clinical Lab Pac, HP E.E. Pac I, HP Games Pac I, HP M.E. Pac I, HP Navigation Pac I, as well as large number of programs published in Users' Library Solutions. For more information and free program downloads visit the RPN-97/67 website: cuveesoft.ch/rpn67

About

Operational Amplifiers Pro

This app provides interactive calculators and reference information for designing and analyzing op-amp circuits. It offers step-by-step explanations and technical data on popular op-amp series, aiding students and engineers in circuit development and prototyping.

Highlights
  • Interactive op-amp circuit calculators
  • Step-by-step explanations and formulas
  • Reference data on op-amps and comparators
  • Support for 14 languages
  • Light and dark mode
  • Advanced calculators and circuit guides (Pro)
  • Full-text search (Pro)
Features
Read full description

Operational Amplifiers Pro is your essential tool for designing and analyzing circuits using op-amps. 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 Pro Version Includes: • Advanced calculators and circuit guides • Full-text topic search • Save favorite circuits for quick access 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 • Popular operational amplifiers description and pinout 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 and Square-Wave Generator • Generator with Adjustable Slope and Duty Cycle 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 Download now and power up your electronics work!

Screenshots

Operational Amplifiers Pro4 screens

Verdict

The call

The clearest difference is ratings volume: RPN at 11 against Operational Amplifiers Pro's 1. RPN also leads on iOS requirement (12.0 vs 17.0). Operational Amplifiers Pro's advantage is device support (3 vs 1). On price, rating, update cadence and ads 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

RPN costs $4.99 and Operational Amplifiers Pro $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for RPN against 5.0 for Operational Amplifiers Pro. That said, the two scores are not equally well evidenced: RPN has 11 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

RPN ships an update every 3 months, Operational Amplifiers Pro every 2 months. The most recent releases landed on October 20, 2026 and October 19, 2026 respectively.

Scorecard3 real differences · 7 level
RPN versus Operational Amplifiers Pro: the parameters behind the verdict, then further details
ParameterRPNOperational Amplifiers Pro
Price$4.99$4.99
Rating4.9 (11 ratings)5.0 (1 ratings) — better
Positive reviews100.0% of reviews—
Number of ratings11 — better1
Update frequencyEvery 3 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPadiPhone, iPad, Mac — better
Requires iOS12.0 — better17.0
Further details — not scored
Size75 MB14 MB
Age rating4+4+
DeveloperCuVee SoftwareALG Software Lab

Customer experience

RPN

All ratings11 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews12 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Operational Amplifiers Pro

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

RPN

No in-app purchases

None

Operational Amplifiers Pro

No in-app purchases

Questions

Is RPN free?
RPN costs $4.99, with no in-app purchases.
Is Operational Amplifiers Pro free?
Operational Amplifiers Pro costs $4.99, with no in-app purchases.
Which has better reviews, RPN or Operational Amplifiers Pro?
Operational Amplifiers Pro is rated higher. RPN averages 4.9 out of 5 from 11 ratings, while Operational Amplifiers Pro averages 5.0 from 1 ratings.
Do RPN or Operational Amplifiers Pro have ads?
Neither RPN nor Operational Amplifiers Pro shows ads.
Which is updated more often, RPN or Operational Amplifiers Pro?
RPN ships an update every 3 months, and Operational Amplifiers Pro every 2 months. Most recently, RPN was updated on October 20, 2026 and Operational Amplifiers Pro on October 19, 2026.

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