Comparison

iCircuit vs System Designer

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

Head to head
About

iCircuit

Design and simulate analog and digital electronic circuits in real-time. This app offers a comprehensive component library, built-in test equipment, and the ability to create custom elements. It's ideal for learning, prototyping, and validating designs without physical components.

Highlights
  • Real-time circuit simulation
  • Extensive component library (300+)
  • Built-in test equipment (multimeter, oscilloscope)
  • Programmable Arduino and PIC microcontroller support
  • Custom element creation and sharing
  • Audio simulation
Features
Read full description

iCircuit is the premier iPhone and iPad app for designing, simulating, and learning analog and digital electronics. Its advanced simulation engine provides real-time, always-on analysis so your circuits stay powered and live, just like working with real components. Use it like a CAD tool: add components, wire them up, and set their properties. But iCircuit is unlike typical CAD apps because it is always simulating. You do not stop to take a measurement or spend time configuring reports. Instead, you just play with the circuit as you normally would, with the power on. Build circuits with over 300 components, from simple resistors and LEDs to programmable Arduinos (Uno, Nano, Mega, ESP8266, ESP32), PIC microcontrollers, and 60 4000/7400-series digital ICs (more available with Pro). Connect elements, adjust values, and instantly see the results. BUILT-IN TEST EQUIPMENT • Multimeter: Probe any point to read voltage, current, and power • Oscilloscope: Track multiple signals with touch-controlled time scale, stacked/unstacked views, FFT analysis, and Bode plots • Gauges: Visualize voltages, currents, and frequencies directly in your circuit • Signal generators and configurable sources EXTENSIVE COMPONENT LIBRARY • Programmable Arduinos (Uno, Nano, Mega, ESP8266, ESP32) • Programmable PIC microcontrollers (assembly and HEX files, more available with Pro) • Power: Voltage regulators (78xx, LM317), sources, dependent sources, power jacks, and simulated antennas • Analog: Resistors, capacitors, inductors, diodes, BJTs, MOSFETs, thermistors, triodes, and tetrodes • Digital: Logic gates (AND, OR, NAND, NOR, XOR), JK and D flip-flops, and 60 4000/7400-series ICs (180+ available with Pro) • ADCs and DACs • Sensors and displays: LEDs, 7-segment, NeoPixels, matrix displays, thermistors • Electromechanical: Motors, servos, SPST/SPDT and DPST/DPDT switches, push buttons, relays, and speakers CREATE CUSTOM ELEMENTS Build sub-circuits and custom elements to componentize your designs and create reusable modules. Share your custom elements with others via the iCircuit Gallery. AUDIO SIMULATION Hear your circuits. Speakers, buzzers, and microphones produce real audio output. Perfect for students learning electronics, hobbyists prototyping projects, and engineers validating designs, all without burning out a single component. ABOUT ICIRCUIT PRO (OPTIONAL) iCircuit is a complete app with a one-time purchase. iCircuit Pro is optional and adds extra components (including more PICs and a larger 4000/7400 IC library) and helps fund ongoing development. Pro is not required for core simulation or everyday circuit design. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

System Designer

Design complex systems using a low-code platform that leverages UML standards. Generate code skeletons and manage components graphically. Run and test your system with dynamic type checking.

Highlights
  • UML-based system modeling
  • Code skeleton generation
  • Graphical component creation
  • MSON format for model definition
  • Dynamic type checking
  • Cross-device synchronization via GitHub
Features
Read full description

System Designer is a low-code development platform for creating systems. No matter the frameworks you use and the code you write, the most important is the model that you define to create your system. System Designer helps you to design this model and to generate the classes and components to build your system. DESIGN YOUR SYSTEM WITH EASE If you look at the different JavaScript frameworks on the market, you will notice that they all have their own way to define a model, generally only with code. System Designer uses UML, a standard, to define your model. So you probably already know how to design in System Designer even if you have never run it. The definition of the model is stored on a JSON format called MSON. With MSON you can define types, classes, one to one / one to many relationships and multi inheritance between classes. CODE THE BEHAVIOR OF YOUR SYSTEM Once you have created your model, System Designer generates the skeletons of all your methods. You only have then to add your code to implement them. System Designer provides you helpers to manage your components. You can easily navigate threw your components to create your application. CREATE COMPONENTS GRAPHICALLY There is no need to code to instantiate a component. Create a component in System Designer is like creating a document in a NoSQL Database. In fact, System Designer acts as an ODM (Object-Document Mapper) to manage your components as NoSQL Documents. RUN YOUR SYSTEM You can run your system directly from System Designer. Because you have defined a model for your application, a Dynamic Type Check is done on every action of your system. All warnings are send and shown in System Designer. DESIGN ON THE GO System Designer can be used on macOS, iPad or any browsers. System Designer has a Github module to synchronize your work between all these apps. You can begin your design on your Mac and then continue it on your iPad.

Screenshots

iCircuit4 screens
System Designer3 screens

Verdict

The call

The clearest difference is price: System Designer at Free against iCircuit's $12.99. System Designer also leads on rating (4.4 vs 3.8) and in-app purchases (none vs 2). iCircuit's advantage is chart position (#172 vs unranked) and ratings volume (134 vs 17). On update cadence, ads 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

CostPrice · In-app purchases · Ads · Monetization

System Designer is free to download; iCircuit costs $12.99 up front. iCircuit sells 2 in-app purchases, starting at $1.99 per month. System Designer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

System Designer holds the better App Store score, 4.4 against 3.8. That said, the two scores are not equally well evidenced: iCircuit has 134 ratings behind it against 17, so its average is the more settled of the two. Written reviews point the same way: 61% of iCircuit's written reviews are positive against 78% of System Designer's.

UpkeepUpdate frequency

iCircuit ships an update every 3 weeks, System Designer monthly. The most recent releases landed on September 24, 2026 and September 18, 2026 respectively.

Scorecard8 real differences · 3 level
iCircuit versus System Designer: the parameters behind the verdict, then further details
ParameteriCircuitSystem Designer
Price$12.99Free — better
Rating3.8 (134 ratings)4.4 (17 ratings) — better
Positive reviews61.1% of reviews77.8% of reviews — better
Number of ratings134 — better17
Update frequencyEvery 3 weeks — betterMonthly
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidFree — better
Best chart rank#172 — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.2 — better15.6
Further details — not scored
Size126 MB7 MB
Age rating4+4+
DeveloperKrueger Systems, Inc.Erwan Carriou

Customer experience

iCircuit

All ratings134 ratings
Positive67.9%
Neutral4.5%
Negative27.6%
Written reviews682 reviews
Positive61.1%
Neutral12.6%
Negative26.2%

System Designer

All ratings17 ratings
Positive88.2%
Neutral0.0%
Negative11.8%
Written reviews9 reviews
Positive77.8%
Neutral0.0%
Negative22.2%

Bugs and requests

iCircuit

Reported bugs

4 issues
  • Oscilloscope and meter functions not working properly
  • Saving and loading circuits can be unreliable
  • Inconsistent behavior when rotating/flipping components
  • Crashes when working with larger or more complex circuits

Requested features

5 requests
  • More components (e.g. transformers, triodes, MOSFETs)
  • Ability to create custom components
  • Frequency domain analysis (Bode plots, FFT)
  • Improved wiring and component placement controls
  • Better support for AC circuits and motors

System Designer

Not enough reviews yet to summarise bugs or requests.

In-app purchases

2 purchases

iCircuit

Subscriptions2
  • iCircuit Pro (Monthly)$1.991 Month
  • iCircuit Pro (Yearly)$14.991 Year
None

System Designer

No in-app purchases

Questions

Is iCircuit free?
iCircuit costs $12.99, and also offers in-app purchases.
Is System Designer free?
System Designer is free to download, with no in-app purchases.
Which has better reviews, iCircuit or System Designer?
System Designer is rated higher. iCircuit averages 3.8 out of 5 from 134 ratings, while System Designer averages 4.4 from 17 ratings.
Do iCircuit or System Designer have ads?
Neither iCircuit nor System Designer shows ads.
Which is updated more often, iCircuit or System Designer?
iCircuit ships an update every 3 weeks, and System Designer monthly. Most recently, iCircuit was updated on September 24, 2026 and System Designer on September 18, 2026.

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