You don't need to learn Raphael.js to use this.
This jQuery plugin uses Raphael.js internally to draw customizable SVG Gauges, and allows you to set/get values by simply using .val()
View README for details
Blogged at: http://terryyoung.blogspot.hk/2013/12/jquery-svg-gauge-plugin-10.html
Click on each gauge to view sample code.
Value setters and getters