A phototransistor is used for its high sensitivity and large current carrying capacity.
Here are some applications of the phototransistor.
Light sensing: They are widely used to detect light and measure the intensity of light.
Automatic light control: it can automatically control the light in street or on the highway. it senses the sunrise and sunset and switches On or Off the connected lights on the circuit.
Object counter: it senses an object when it passes between it and a constant light source. It triggers the connected circuit when the object interrupts the incident light.
Opto-coupler: it electrically isolates two circuits and optically connects them using light pulses to protect low voltage circuits from high voltage circuits.
Punch card reader: it is widely used in punch card readers.
Shutter control: it controls the opening of the camera shutter based on the intensity of the light falling on its lens.
Alarms: it is used in burglar alarms by detecting the presence of a person passing through it. Fire alarm and smoke alarm also uses phototransistor.
Proximity sensor: it detects presence when something comes in its range such as in a smartphone that turns off the screen when it’s near your ear.
Infrared Sensing: sensing IR at night time allow it to use as a night vision device.
- Encoder
- Optical remote control
- Printer and photocopier etc.
