is the answer ABCor D Light striking the device causes a b

** is the answer A,B,C,or D **

\"Light striking the device causes a base current which is then amplified ....\" was referring to a/an:

a. laser

b. photodiode

c. bipolar transistor

d. phototransistor

Solution

Light striking the device causes a base current which is then amplified was referring to a

d.phototransistor

A phototransistor is a light-sensitive transistor. A common type of phototransistor, called a photobipolar transistor, is in essence a bipolar transistor encased in a transparent case so that light can reach the base–collector junction. The electrons that are generated by photons in the base–collector junction are injected into the base, and this photodiode current is amplified by the transistor\'s current gain (or h_fe). If the base and collector leads are used and the emitter is left unconnected, the phototransistor becomes a photodiode. While phototransistors have a higher responsivity for light they are not able to detect low levels of light any better than photodiodes.