If you’re going to do a job right, you need the right tools. Today, the definition of tool goes beyond wire crimpers and multimeters. It now includes smartphones and the apps that make them crucial to a contractor’s success. The following are some of the apps that contractors could consider using.


For Android operating systems


ElectroDroid is a simple, powerful collection of electronics tools and references. There is a free version (with ads) and a Pro version ($2.99 without ads), which offers more features, including resistor and inductor color-code decoders, resistance and reactance calculators, voltage dividers and voltage drop calculators, and more. You can prototype your circuit in the tool and calculate whether the result will look the way you like, and you can use the app’s extensive reference guide to review the components you need, look up pin-out connectors and more. The app also supports plug-ins to expand functionality, including a PIC and AVR microcontrollers database, simulators and a parts search. The app has more than 78,000 reviews and a 4.7 star rating on Google Play.


Electrical Wiring Pro (EWP) 2014 ($3.99) has been updated from the 2011 version and includes calculations based on changes to the 2014 National Electrical­ Code (NEC). A working electrician wrote it for fellow electricians, power engineers and other electrical professionals. The more than 40 electrical calculators and tools make it possible to perform calculations per NEC 2014, 2011, 2008 or 2005 editions, and features include residential/load calculations, ampacity and wire sizes, more than 700 locations with ambient temperatures, boxes and cover calculations, conduit fill, voltage drop, motor and transformer sizing, and wiring and device configuration. New features, per the 2014 NEC, include residential service/feeder calculations using the 83 percent method and revised electrical nonmetallic tubing sizing. The latest version has 94 reviews on Google Play with a 4.6 star rating. 


Ohm’s Law Calculator (free) includes the Ohm’s Law calculator/Watt’s Law calculator that figures any two unknown values given two known values and resistor calculators that figure bands given value or value given bands. The app has preferences/lock functions to allow values to either remain fixed or auto range to appropriate International System of Units; a resistor calculator that automatically determines three, four or five band; voltage, current, and power calculators; and a clean, intuitive interface. Recent updates added exception handling and better handling of parsing numbers from input strings. Other key features are multiple options for calculating each value, accurate calculation of the output with respect to changes in the input/options/units, the calculation of values of higher order, and a database of formulas and definitions. The app has 192 reviews with a 4.1 rating on Google Play.


For Apple iOS operating systems


ElectricalToolKit (free) has a calculator for everything from capacitive and inductive reactance to resistor color codes and includes electrical wiring diagrams and pinouts, according to Software Advice. This app is intended to be smart enough to recalculate circuit values when the user edits any input data. Features include seven different three-way switch, basic light, and four-way switching diagrams as well as wall outlet wiring diagrams, a service entrance ground size requirements table, grounding conductor size calculator, and Ohm’s Law and voltage-drop calculators. On iTunes, the app has 3,825 ratings and an average of 3 stars.


iCircuit ($9.99) is an app for experimenting with and designing electrical circuits. Its simulation engine can handle both analog and digital circuits and features real-time, always-on analysis. It is used like any CAD program for adding elements, connecting them together and setting their properties. iCircuit constantly simulates in the background. There are more than 30 elements that can be used to build circuits, and the app has everything from simple resistors, to switches, MOSFETs and digital gates. Features include a multimeter to read circuit voltages and currents instantly and the ability to add values to the built-in oscilloscope. iCircuit supports elements such as signal generators; voltage, current and dependent sources; speakers; microphones; buzzers; DC motors; LEDs; a seven-­segment display and driver; an antenna with simulated AM/FM signals; and more. It has a 4+ star rating on iTunes with 15 reviews.


Electrical Formulator Pro ($6.99) combines more than 250 formulas and 150 charts. The charts include motors, power demand, wiring, and voltage drop and safety codes. The basic program calculates both alternating current (AC) and direct current (DC) amperes, kilowatts, horsepower, efficiency, power factor, watts, current, power, resistance and voltage. It includes formulas to calculate total resistance, capacitance, voltage drop and transformers. Also included are helpful Btus, kilowatts and lumens conversions.