Ohm's law and the power law describe the relationship between the following four electrical entities: Entity..............Unit.......Symbols Voltage..........Volts......V Current...........Amps.....A, I Resistance.....Ohms....., R Power............Watts.....W Ohm's law: Voltage = Current x Resistance Power law: Power = Voltage x Current Set any two, and the other two can be calculated. This application allows you to continually lock one parameter and input another, enabling rapid "what-if" recalculation. Use the keypad to enter a value then tap on the parameter you want to set. It is now fixed, as shown by the padlock symbol. Enter another parameter and the remaining two are calculated. The most recently entered parameter becomes the new fixed one. You can alter which parameter is fixed by tapping it when the input box is empty, or by dragging the padlock to it. You can "Freeze" a parameter with a long press until it changes color. Now alter any of the other three as required. To unfreeze, with the input box empty, tap any other parameter. The value of the fixed parameter may not be changed. If you attempt to do so, the padlock will flash. In this case, fix another parameter first. Available in the following Languages: English, French, German, Swedish, Russian, Polish, Spanish, Italian, Traditional & Simplified Chinese.