PHYS-1500 PHYSICAL MODELING FALL 2006
A resistor is familiar to most students of high school physics. Its symbol is:
The potential difference (or voltage) across a resistor is proportional to the current passing through it.

V = – iR , where i is the current, and R is the resistance. The minus sign means that the potential decreases in the direction that the current flows.
A capacitor is symbolized by:
The potential difference (or voltage) across a capacitor is proportional to the charge on it.

V = – q/C , where q is the charge, and C is the capacitance. The minus sign means that the potential decreases in passing from the positively charged plate to the negatively charged plate.
An inductor is symbolized by:
The potential difference (or voltage) across an inductor is proportional to the rate of change of current through it.

V
 
L di
, where i is the current, and L is the inductance. The minus sign dt means that the potential decreases in the direction of increasing current.
A source of emf is often symbolized by:
The longer parallel line indicates the side that is at higher potential (the positive side).