phototransistor

As nouns the difference between transistor and phototransistor

is that transistor is while phototransistor is any semiconductor device whose electrical characteristics are light-sensitive.

As nouns the difference between photoresistor and phototransistor

is that photoresistor is an electronic component whose resistance is inversely proportional to the intensity of incident light; a photoconductor while phototransistor is any semiconductor device whose electrical characteristics are light-sensitive.

As nouns the difference between triode and phototransistor

is that triode is a thermionic valve containing an anode, a cathode, and a control grid; small changes to the charge on the grid control the flow from cathode to anode which makes amplification possible while phototransistor is any semiconductor device whose electrical characteristics are light-sensitive.