Gauges are really great symbolic elements. They can be used to convey ideas such as speed, power, energy, etc – it’s limitless! I created this generic gauge illustration to incorporate it into a series of images in my royalty-free image collection, and I’m offering it here as a free download since I no longer have a need for it. Of course I’ve simplified it a bit from my original, but all the important elements are there and you can customize it however you wish.
Note that many of the layers in the attached PSD file are fully-scalable vector shapes. That means that you can scale this up or down with no loss of quality. Not every layer is scalable, but it is a versatile illustration.