ABSTRACT
Leaving out the precise details of how the components are connected and how they work, we can represent the circuit on the left by a system diagram:
This shows that the system has two parts: • The LDR, which receives input from the
surroundings: an amount of light. • The meter, which provides output, in this
case, a measurement of voltage. In this system, the two parts are directly linked. As we shall see later, most systems have more than two parts.
