d) Diode/LED/LDR

ci) I-V characteristics of resistor, filament lamp, thermistor, diode, and light-emitting diode (LED)

d) light-dependent resistor (LDR); variation of resistance with light intensity

diode/LED

for a positive current and potential difference

• potential difference → not directly proportional to current

• resistance = decreasing

for a negative current and potential difference

• potential difference → not directly proportional to current

• resistance = infinite

non-ohmic conductor

LDR → resistance and light intensity are inversely proportional

• light intensity increases → number density of electrons increases