From c6c9959ca199ea8318a982fda19e64a7453a1aee Mon Sep 17 00:00:00 2001
From: samreid <reids@colorado.edu>
Date: Sun, 5 Nov 2017 17:14:14 -0700
Subject: [PATCH] Cleanup in  Voltmeter, see
 https://github.com/phetsims/faradays-law/issues/86

---
 js/faradays-law/model/Voltmeter.js            | 16 ++++++++--------
 js/faradays-law/view/FaradaysLawScreenView.js |  4 ++--
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/js/faradays-law/model/Voltmeter.js b/js/faradays-law/model/Voltmeter.js
index ad371773..e50bf810 100644
--- a/js/faradays-law/model/Voltmeter.js
+++ b/js/faradays-law/model/Voltmeter.js
@@ -36,7 +36,7 @@ define( function( require ) {
     this.needleAngularAcceleration = 0;
 
     // @public {NumberProperty} Needle angle in radians. This drives both the needle location and the light bulb brightness.
-    this.thetaProperty = new NumberProperty( 0 );
+    this.needleAngleProperty = new NumberProperty( 0 );
 
     // @private - input voltage to meter
     this.signalProperty = new NumberProperty( 0, {
@@ -59,18 +59,18 @@ define( function( require ) {
       // empirically determined to make the needle move the correct amount and direction.
       this.signalProperty.set( -0.2 * (this.model.bottomCoil.emfProperty.get() + this.model.topCoil.emfProperty.get()) );
 
-      this.needleAngularAcceleration = NEEDLE_RESPONSIVENESS * (this.signalProperty.get() - this.thetaProperty.get()) - NEEDLE_FRICTION * this.needleAngularVelocity; //angular acceleration of needle
-      this.thetaProperty.set( this.thetaProperty.get() + this.needleAngularVelocity * dt + 0.5 * this.needleAngularAcceleration * dt * dt ); //angle of needle
+      this.needleAngularAcceleration = NEEDLE_RESPONSIVENESS * (this.signalProperty.get() - this.needleAngleProperty.get()) - NEEDLE_FRICTION * this.needleAngularVelocity; //angular acceleration of needle
+      this.needleAngleProperty.set( this.needleAngleProperty.get() + this.needleAngularVelocity * dt + 0.5 * this.needleAngularAcceleration * dt * dt ); //angle of needle
       var omega = this.needleAngularVelocity + this.needleAngularAcceleration * dt;
-      var alpha = NEEDLE_RESPONSIVENESS * (this.signalProperty.get() - this.thetaProperty.get()) - NEEDLE_FRICTION * omega;
+      var alpha = NEEDLE_RESPONSIVENESS * (this.signalProperty.get() - this.needleAngleProperty.get()) - NEEDLE_FRICTION * omega;
       this.needleAngularVelocity = this.needleAngularVelocity + 0.5 * dt * (this.needleAngularAcceleration + alpha);
 
       // Clamp the needle angle when its position, velocity, and acceleration go below a threshold so that it doesn't
       // oscillate forever.
-      if ( Math.abs( this.needleAngularAcceleration ) !== 0 && Math.abs( this.needleAngularAcceleration ) < ACTIVITY_THRESHOLD &&
-           Math.abs( this.needleAngularVelocity ) !== 0 && Math.abs( this.needleAngularVelocity ) < ACTIVITY_THRESHOLD &&
-           Math.abs( this.thetaProperty.get() ) !== 0 && Math.abs( this.thetaProperty.get() ) < ACTIVITY_THRESHOLD ) {
-        this.thetaProperty.set( 0 );
+      if ( this.needleAngularAcceleration !== 0 && Math.abs( this.needleAngularAcceleration ) < ACTIVITY_THRESHOLD &&
+           this.needleAngularVelocity !== 0 && Math.abs( this.needleAngularVelocity ) < ACTIVITY_THRESHOLD &&
+           this.needleAngleProperty.get() !== 0 && Math.abs( this.needleAngleProperty.get() ) < ACTIVITY_THRESHOLD ) {
+        this.needleAngleProperty.set( 0 );
         this.needleAngularVelocity = 0;
         this.needleAngularAcceleration = 0;
       }
diff --git a/js/faradays-law/view/FaradaysLawScreenView.js b/js/faradays-law/view/FaradaysLawScreenView.js
index 97345764..8c188fcd 100644
--- a/js/faradays-law/view/FaradaysLawScreenView.js
+++ b/js/faradays-law/view/FaradaysLawScreenView.js
@@ -50,8 +50,8 @@ define( function( require ) {
     this.aligner = new Aligner( model, bottomCoilNode.endRelativePositions, topCoilNode.endRelativePositions );
 
     // voltmeter and bulb created
-    var voltmeterNode = new VoltmeterNode( model.voltmeter.thetaProperty, tandem.createTandem( 'voltmeterNode' ) );
-    var bulbNode = new BulbNode( model.voltmeter.thetaProperty, {
+    var voltmeterNode = new VoltmeterNode( model.voltmeter.needleAngleProperty, tandem.createTandem( 'voltmeterNode' ) );
+    var bulbNode = new BulbNode( model.voltmeter.needleAngleProperty, {
       centerX: this.aligner.bulbPosition.x,
       centerY: this.aligner.bulbPosition.y
     } );