More sensitive

Available different sizes and specifications

Cannot be used to determine precise light levels

Made of low resistance material with few holes

Silicon

Germanium

Aluminium

Cadmium sulfide

Voltage rectification

Demodulation purpose

Controls of street lighting systems

To generate oscillations

Primary cells

Rechargeable cells

Light dependent resistor

Voltage dependent resistor

By the bias voltage to the photo transistor

By the external signal to the transistor

By IR light produced inside the package

By the light sensitive receiver inside