Here's a calculator that every technician, maintenance person, or home hobbyist should have. This Electrical Calculator contains tons of useful calculations used to figure out the every day used formulas (ohms, amps, volts, etc.), or for those formulas that are hard to find or seldom used. This is great for homework or on the job. KMB Electrical Calculator includes an easy to use 3D resistor color code reader which works with variable inputs and outputs. The Volt, Amp, and Ohm function are free to use.