The *** ORIGINAL *** Electronic Toolbox Pro App
"The best and most complete Electronics App on the App Store" for Professionals, Hobbyists, Makers, HAMs and Students right at your fingertips!

Best of all: Continuously improved since 2009 - FOR FREE - NO IN APP PURCHASE - NO FAKE REVIEWS!

What users wrote about this app:

Well worth the money *****
I researched all EE apps before buying this one and I have to say that this one is the best by far. The developer is very accommodating to requests and suggestions and provides updates frequently. Very, very happy with this app.

Simply brilliant *****
I don't normally review apps but I was so impressed with this one I felt I had to make a brief comment. Buy it, I promise you won't be disappointed.

Supports iOS 13 back to iOS 10 and all Apple iPhone and iPad models including 7, 8, X, XS, XR, plus, max and all iPad pro models.

See the online Manual at

Feature Highlights:
■ Circuit Editor
■ Most comprehensive and complete Electronics app available
■ Designed for Novices as well as Experts
■ Numerous individual tools from "A" like ASCII Table to "Z" like Zener Diode calculation. If something is missing, just let me know
■ Provides wide variety of simple and complex tools, such as the resistor color code conversion to the PCB Trace width tools
■ Various calculation tools available, such as the NE555 circuit calculation and the passive cooling calculator
■ Includes reference tools with millions of component specs for ICs, Transistors, FETs, Controllers with parametric searches, pinout and cross reference information, and complete datasheets
■ Provides information about Batteries, Drill sizes, Hybrid Amplifiers, Socket pinouts, package sizes and much more
■ Includes conversion tools, such as the Unit conversion tool, the HEX/Decimal/Float Tool, Frequency and AWG / SWG tools
■ Parametric search for Components with certain specs and cross references
■ Global search for terms or components across all tools
■ Customizable arrangement of tools for quick and easy access
■ Includes a scientific desktop calculator, a frequency generator, and an oscilloscope
■ Comprehensive reference glossary (english only)
■ Content can be updated "over-the-air" and amended quickly and easily
■ Store diagrams, documents, and specs of a project
■ iCloud support
■ No ads or in-app purchases
■ Can be used without Internet access
■ Special keyboard available for quicker entry of SI units
■ And much more...

Now also includes reference tools for major boards like RaspBerry Pi, Arduino, BeagleBone, TI-Launchpad, Nano Pi, Orange Pi, Banana Pi, Odroid, Cubieboard and SparkFun!

For further information about this App, just have a look at my website: ■ ■ or just send me an E-mail.

The new Version of the app has just been released and as always, this update is FOR FREE to all users of Electronic Toolbox.

At this point, many thanks for the ideas and suggestions I have received from the huge user community. You helped me to keep on improving my app with every new update.

This App will continue to live and grow over the time. So I still look forward to all additional ideas, suggestions or even criticism so that I can continuously improve my App.

Best regards,


Read more on :

What’s New

Version 13.0.2

This update contains several changes and improvements:

■ Additional iOS 13 compatibility

- a new File and PDF Viewer has been implemented
- iOS 13 page sheets are now supported
- and several additional changes to support iOS 13 have been implemented
- The minimal iOS Version requirement is now 10

■ Bug fixes

- Bug fixes in the C-Plate tool
- Bug fix of the Components tool which could only opened once
- Due to the new PDF Reader, data-sheets will now rotate correctly
- Printing from inside the Database tools (e.g. Transistors) now work correctly
- A bug which prevents to import Online projects was fixed (basically an iOS 13 bug)

■ SamacSys tool

I found that this tool often was underestimated. It is indeed a very powerful tool to find information like specs, data sheet and pin out of literally any component. The tool is now called Comp. Search to better suit to it's purpose. I have also implemented some improvements to this tool.

■ Attenuator tool

This tool now also calculates backwards based on the selected E-Series

■ Tables tool

- 3D Printing Filament types added
- Power over Ethernet POW Classes added

■ Circuits diagrams

One of the larger improvements is the use of the internal Circuit drawing feature for the tool diagrams. This way, the circuits (e.g. for the OpAmp Tool) benefit from the following improvements:

- Improved drawing quality
- Resistors will now either be displayed in Zig-Zag US or IEEE Style (depending on the country setting)
- Where possible, the circuits now show the calculated component values inside the diagram
- All tools now offer Printing and PDF Exporting which also includes the circuit diagram

■ Circuit Editor

- New Setting: "Adjust board to fit" under (File -> Board settings) allows to change the board size to fit the whole circuit so you don't have to move components around if the board is too small.
- Circuits can now also be printed
- It is not possible to save circuits as PDF or sent them as circuit file via Email from inside the Circuit Editor

■ Improved File Viewer, Print and export capabilities

Either from inside the tools or from inside the File Viewer, content like the Tool results can now be exported as PDF as local file or printed

■ Other improvements

- A new Tool SMPS for calculating Flyback Transformers for Switched Mode Power Supplies as been added
- Several images have been re-created in higher quality
- The Formulas tool has also been improved

In case of questions, issues or suggestions, please use the Support button inside the App of the Form on the website.

Thank you so much for your support.

Please let others know if you like this App to keep it going.

Thank you so much!

Best Regards,


Ratings and Reviews

4.6 out of 5
125 Ratings

125 Ratings


Convenient Practical for Hobbyists AND Engineers

Marcus has developed a great iPhone app for electronic hobbyists and engineers to have handy in your pocket. It provides handy reference to pinouts, specs, component markings, formulas, calculators, electronic related physics reference, on and on, in an easy to navigate and use format.
I use it to explore microcomputer chips, both pic and atmel, when beginning a project away from my computer and with a little time to kill while waiting for whatever.
Even when at my computer, it is great to look up this and that without having to radio-button back and forth between so many windows, or having to print something out just to refer to while I'm working.
Marcus has been updating and expanding this app for years now, and doesn't keep hitting his customers up to pay and pay for updates like some developers do, nor does he abandon the app when iOS requires compatibility updates.
If you are an active hobbyist or a napkin-doodling engineer, you will not regret purchasing this app!

Michael Timbes ,

Extremely Comprehensive-Worth it!

I've been trying to learn how to create circuits for the past year or so and this app is by far the greatest reference I've come across. In addition to the vast amount of data sheets and various formulas, there is a way to make a list of parts one may need to complete a project which is very useful. Finally, the developer is very active and always looking for ways to improve the app, if he/she keeps that mind set(without adding too much in one app), this may be the go to reference for electronics and components. Great job and I definitely recommend the app!

TylerHi1999 ,

Every Electronics Person Should Get This App!

Before I got this app, i sent the developer a email on whether you could design your own Circuit Schematics. They answered me back in less then 24 hours. I got the app. Went to go make a test Schematic, just to get the hang of it. I was blown away! It is better then I could have imagined!

They also have parts where you can solve the value of different components. For example, you can solve anywhere from a Resistor, to a Coil.

As a student doing online college to become a Electronics Technician, this app is a huge help! Glad I found it!

If you ever have a question, they answer it, and they do it quite quickly!

Whether you are a Student like me, or been in the Electronics industry for years, Electronic Toolbox Pro is a must for anyone who dose Electronics!

Glad I found this app! Thanks for making it Marcus Roskosch!


Marcus Roskosch
226.3 MB

Requires iOS 10.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, French, German, Italian, Simplified Chinese, Spanish, Traditional Chinese

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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