1、1.2 Circuit Model The physics of a torch depends on a circuit as shown in Fig. 1. A typical torch consists of a battery to provide the voltage, a switch button to control the on or off state, and a bulb which transfer electricity to light. These are connected through wires to form up a circuit. Figu
2、re1: Circuit for a torch When we analyze a circuit, it is obviously impractical to draw the actual images for each element. Instead, we use abstract symbols to represent the actual circuit elements, as shown in Fig. 2, so as to make things easier. SourceSwitchResistor Figure 2: Circuit model for a t
3、orch In Fig.2, the battery is abstracted as a constant voltage source; the button is abstracted as a switch; and the bulb is abstracted as a resistor. All the circuit elements are connected through lines, and such an abstract circuit is called as a circuit model. The circuits that we will discuss in our next lectures are all the corresponding abstract circuit models.
