Fototransistori

Fototransistori are semiconductor devices that combine a transistor and a photodiode. They are essentially bipolar junction transistors whose base region is exposed to light. When light strikes the base-collector junction, it generates electron-hole pairs. These charge carriers are then swept across the junction, effectively creating a base current. This base current then controls a much larger collector-emitter current, similar to a regular transistor. Therefore, a fototransistori amplifies the signal generated by the incident light.

Fototransistori are typically housed in a package with a transparent window or lens to allow light to reach the sensitive junction. They are available in two main configurations: phototransistors with a base connection and those without. A base connection allows for external biasing and control of sensitivity, while phototransistors without a base connection are directly controlled by light intensity.

Their applications are widespread and include light sensors, optical switches, encoders, and in remote control systems. They are particularly useful in situations where non-contact sensing is required or where a small, integrated light-sensitive component is needed. Fototransistori offer a good balance of sensitivity and speed for many common sensing tasks.