ElectroDroid is a simple and powerful collection of electronics tools and references.
This is the free version which contains ads; you can also buy from the Market the PRO version of the app to support the developer unlock more features and get rid of the ads.

The app includes:
• Resistor color code decoder (3-6 bands);
• SMD Resistor Code;
• Inductor color code decoder;
• Ohm’s law calculator;
• Reactance/Resonance calculator;
• Voltage divider;
• Resistors ratio value/series/parallel;
• Capacitor charge calculation;
• Operational amplifier;
• LED resistor calculator;
• Adjustable voltage regulator/LM317 calculator;
• Heat dissipation;
• Battery Life calculator;
• Inductor design tool;
• Voltage Drop calculator;
• PCB Trace Width calculator;
• Simple Filters calculator;
• NE555 calculator;
• Power Calculator;
• Decibel Converter;
• Frequency Converter;
• Analog-Digital Converter;
• Y-Δ Transformation;
• Port pin-out (USB Serial Parallel Ethernet RJ SCART DVI HDMI S-Video VGA VESA Display Port FireWire Jack RCA XLR/DMX ATX Power PC Molex EIDE SATA PS/2-AT MIDI/Game port Apple 30-pin PDMI OBD-II 25-pair phone cable color code Color Code for Fiber Optic Cables; ISO connector for car audio; Arduino pin-outs);
• Resources (Resistivity table; Table of standard resistors and capacitors; Capacitor marking codes; AWG and SWG Wire size; Ampacity Table; Symbols and Abbreviations; Circuit Schematic Symbols; SI Units prefixes; Battery info; Boolean logic gate and algebra Theorems; 7400 info and pinout; ASCII codes Batteries list 78xx IC ChipDB IC pinouts Switch Information Decibel Table PIC ICSP/AVR ISP SMD Package Size Radio frequencies);
• Full support for EIA resistor series for all calculators;
...and more to come!

The app has also support for plugins to expand functionality of the application (e.g. PIC and AVR micro-controllers Database simulators parts search).

If you like the program please rate it and buy the full version to support the development.
Electrodroid PRO link: https://play.google.com/store/apps/details?id=it.android.demi.elettronica.pro

For FAQ and full change-log visit http://electrodroid.it