Control circuit
The control circuit block is the electronic component that receives information from the input components, processes that information and controls the output components. For the purposes of this book, the control circuit will be the Arduino but keep in mind it is not required that we use the Arduino for the control circuit. We could create our own control circuit or use another type of microcontroller board like the Raspberry Pi or BeagleBone Black.
This block diagram gives us a high-level view of our Arduino projects. The first thing that we will need to understand is what ties these blocks and the components in the blocks together. For this, we will need to have a basic understanding of electronics and electricity. Let's begin by looking at some tools and common electronic components. We will start by looking at probably the most important tool we have, in our toolbox, to help us with electronic projects: the multimeter.