revise currentAmplitude doc, #130

doc/model.md

@@ -13,7 +13,7 @@ are provided, e.g. `BarMagnet`.  Code can be found [here](https://github.com/phe
 
 **B-field**: a synonym for magnetic field.
 
-**Current amplitude**: A percentage with range [-1,1] that describes the amount of current relative to the 
+**Current amplitude**: A value with range [-1,1]. The magnitude describes the amount of current relative to the 
 maximum current that may be induced in the model. The sign indicates the direction 
 of the current. View components use this value to determine how they should respond to induced current. 
 For example, deflection of the voltmeter needle, brightness of the light bulb, and speed of

js/common/model/Coil.ts

@@ -78,10 +78,10 @@ export type CoilOptions = SelfOptions & PickRequired<PhetioObjectOptions, 'tande
 
 export default class Coil extends PhetioObject {
 
-  // This is a quantity that PhET made up. It is a percentage [-1,1] that describes the amount of current relative to
-  // some maximum current in the model, and the sign indicates the direction of that current. View components can use
-  // this value to determine how they should behave -- eg, how far to move a voltmeter needle, how bright to make a
-  // light bulb, and how fast to move electrons.
+  // This is a quantity that PhET made up. It is a value in the range [-1,1]. The magnitude describes the amount of
+  // current relative to some maximum current in the model. The sign indicates the direction of that current. View
+  // components can use this value to determine how they should behave -- eg, how far to move a voltmeter needle,
+  // how bright to make a light bulb, and how fast to move electrons.
   public readonly currentAmplitudeProperty: TReadOnlyProperty<number>;
   private readonly currentAmplitudeRange: Range;