"Very useful" by MakerMaker
Incredibly handy for anyone working in electronics. Perfect for engineers and non-engineers alike.

"Just what this hobbyist needs" by JoshuaUnwin
I love the clean look and focused tools in this app. It has earned a spot on my first home screen...

Circuit Playground simplifies electronics reference & calculation so you can have more fun hacking, making, & building your projects! This app is designed for both iPhone and iPad.

• Decipher resistor & capacitor codes with ease
• Calculate power, resistance, current, and voltage with the Ohm's Law & Power Calc modules
• Quickly convert between decimal, hexadecimal, binary or even ASCII characters
• Calculate values for multiple resistors or capacitors in series & parallel configurations
• Store, search, and view PDF datasheets
• Access exclusive sneak peaks, deals & discounts at Adafruit Industries

All that, plus updates with additional features & enhancements - MANY NEW CALCULATORS AND TOOLS being added! Not on iOS? An Android version is in the works :) For now, if you'd like to support a cool Android app and developer check out ElectroDroid. Please scroll down here and watch the HD video below about Circuit Playground and check out the screen shots!

Circuit Playground's 1.6 update brings another heaping helping of electronics assistance to our highly nutritious iOS app. Be sure to grab it fresh from the App Store if you haven't already. Let's dig in to what's new on the menu in 1.6 -

• Resistor Divider Calculator

Enter any three of the four values: Vin, Vout, R1, & R2 - and your voltage divider is ready for the breadboard.

• Heat Sink Calculator

Make sure that heat sink can keep your component (relatively) cool while in use - provide the top four values, then enter Power or Junction Temp to calculate the remaining. Temperature can be given in Fahrenheit or Celsius.

• Wavelength to Color Converter

It's a little tough to visualize an LED's color when you only have its light wavelength go by. Input that nanometer value into the Wavelength to Color Converter for a preview of the color + relevant RGB/Hex values. Alternatively - use the color slider to find a color's wavelength.

• Trace Width Calculator

Ensure your PCB traces can handle your circuit's current - calculate the required trace width by providing 4 values for your project. Includes unit options for temperature & length values.

• Quarter Wave Calculator

Find the antenna length you'll need to use for a given frequency, or the corresponding frequency for a given length. Length can be specified in feet/inches or metric value.

• New Pinouts for connectors, ICs, & boards

We've added a bunch of useful pinout diagrams to the app including - Raspberry Pi GPIO, MAX232, LM386, 74HC595, USB (A&B), RS232 (DB-9), VGA (DB-15), Ethernet (RJ-45), 16x2 LCD, 78xx, & 78Lxx

• Show & Tell more!

Show & Tell now lets you share multiple pics & video with Adafruit. Choose up to 3 photos and/or 1 video clip to represent your project - tap a thumbnail image to review each piece of media or remove it from your submission. Of course you can also use your iPad/iPhone/iPod's camera to grab new pics or video - each one will automatically be saved to your device's photo library.

Also - Circuit Playground 1.6 also adds support for iOS 6 & requires iOS 4.3 or later. Changing calculator pages on iPad can now be done with a two-finger swipe across the main view. Circuit Playground 1.6 is available now on the App Store and is a free update for existing users. Bon appetit!

Circuit Playground - Made with love by Adafruit, Collin Cunningham, Limor Fried, Daigo Kawasaki, Mosfet and Phillip Torrone

We also have a paper tool :) We're excited to share this Resistor Helper you can download and make yourself. It's the newest tool in our Circuit Playground family-- when you can't get to your iPhone or iPad, use paper! One side helps you read 4-band types and the other side takes care of 5-band types. The Resistor Helper is on Thingiverse as a PDF (with Illustrator editability preserved). Designed by Adafruit with Matthew Borgatti. You can also grab the PDF on github. Use and enjoy! Tutorial also on Instructables and Make: Projects (blog here).

Circuit Playground* (0:03)