5.3 Non-linear resistor For general media, the relation btwn I and v may be non-Inear Example 1. A incandescent lamp(see Fig 5-5) has a resistance that depends on the temperature so that I-V relation is non-linear. If the lamp is kept at a constant temperature its I-v relation is linear and obeys Ohms law 202 Figure 5-5 Current-voltage relationship for a 60-watt incandescent lamp