At the Integrated Circuit (IC) level, the three principle constituents of a computer system are:
Whether the IC forms part of what is formally recognised as a computer system doesn't matter, as the components and concepts are the same. These are explained below:
A resistor can be thought of in terms of a water pipe.
As a pipe becomes narrower or longer, more pressure (or voltage, in an IC) is required, in order to achieve the same rate of flow. The resistance of a resistor is measured in Ohms.
Capacitors are responsible for storing charge, and can be likened to a water storage tank.
The more water that is pumped into the tank, the more force is required in order to add additional water (or charge, in an IC). The amount of charge that can be stored by a capacitor is known as capacitance.