Key Concepts

• • Ohmic: straight line through origin — resistance R = V/I is constant (Ohm's law holds)
• • Filament lamp: I increases sub-linearly — R rises as the filament heats up
• • Diode: negligible current until ~0.7 V (silicon), then exponential growth in forward bias
• • In reverse bias, diode blocks current until the breakdown voltage is reached
• • The gradient at any point on a V-I curve is 1/R (the dynamic resistance)