iCircuit vs System Designer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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/
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.
- UML-based system modeling
- Code skeleton generation
- Graphical component creation
- MSON format for model definition
- Dynamic type checking
- Cross-device synchronization via GitHub
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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
Verdict
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
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.
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.
iCircuit ships an update every 3 weeks, System Designer monthly. The most recent releases landed on September 24, 2026 and September 18, 2026 respectively.
| Parameter | iCircuit | System Designer |
|---|---|---|
| Price | $12.99 | Free — better |
| Rating | 3.8 (134 ratings) | 4.4 (17 ratings) — better |
| Positive reviews | 61.1% of reviews | 77.8% of reviews — better |
| Number of ratings | 134 — better | 17 |
| Update frequency | Every 3 weeks — better | Monthly |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Paid | Free — better |
| Best chart rank | #172 — better | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.2 — better | 15.6 |
| Further details — not scored | ||
| Size | 126 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Krueger Systems, Inc. | Erwan Carriou |
Customer experience
iCircuit
System Designer
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
iCircuit
- iCircuit Pro (Monthly)$1.991 Month
- iCircuit Pro (Yearly)$14.991 Year
System Designer
No in-app purchases
Questions
Is iCircuit free?
Is System Designer free?
Which has better reviews, iCircuit or System Designer?
Do iCircuit or System Designer have ads?
Which is updated more often, iCircuit or System Designer?
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