What characteristic do phototransistors possess compared to standard transistors?

Phototransistors have a unique characteristic of being sensitive to light, which differentiates them from standard transistors. This sensitivity allows phototransistors to operate as switches or amplifiers in response to light exposure. When light strikes the phototransistor, it generates charge carriers, resulting in a current flow through the device. This property makes phototransistors particularly useful in applications such as light detection, optical communications, and automatic lighting systems, where they can control devices based on ambient light levels.

In comparison, standard transistors rely on electrical signals for their operation rather than light. While characteristics like voltage ratings, power consumption, and frequency response are important in both types of transistors, the defining feature of phototransistors is their ability to respond to light stimuli.