---

Phototransistor

A phototransistor is similar to a bipolar transistor in that it has an emitter, base, and collector. The control electrode of the phototransistor is connected, together with its second main electrode, to a first supply potential of the light sensor. The phototransistor is operated in a weak inversion condition, which gives it a linear output characteristic of the photocurrent or a logarithmic output characteristic of the photovoltage as a function of the received illuminance. Phototransistors are generally more sensitive than photodiodes to changes of illumination, they are preferred as switching devices in some applications where fairly small changes in the level of illumination are expected. The phototransistor works both as a PN junction photodetector and an amplifier of the current generated by incident light. Phototransistors respond to light energy that affects the silicon lattice near and within a PN junction. Some phototransistors are provided with a shunt resistor that establishes a threshold optical signal level below which the light is insufficient to provide an electrical signal. A phototransistor is generally formed utilizing a process of manufacturing semiconductor devices on a monocrystalline semiconductor substrate, and a light signal processing circuit including normal transistors.

---

---

---

There's no product listing here. Be the first to submit your product information.

---