At the TechShop in Chandler, Arizona (techshop.ws
) they have a "Junk" bin. As a result of this there are a lot of useful things especially electronic devices. The upside of this is that the part is free but the down side it is difficult to know what the power requirements are. In this instructable I will go over how to test things safely and provide some tips to help you out. Keep in mind that this form of testing really applies to things that you can directly sense with one of your five senses such as LED's.