The ICON Digital Circuit Tester is a new test light that is available at Harbor Freight. Unlike an old-school device, this light provides a bright red (positive) or green (negative) LED numeric ...

As well as building real-life circuits you can also use circuit simulation software on your Mac. This enables you to test out parts and components in a safe environment.

This is a multifunction RJ45 network cable tester. It is the design of the network cable (RJ45) test, and telephone (RJ11). It is cheap and easy to use.