1. 
   Phototransistor
   A transistor in which an amplified current is generated when light falls on the base-collector junction.
   Found op http://www.encyclo.co.uk/visitor-contributions.php
   
   
2. 
   phototransistor
   transistor in which the current produced by the photoelectric effect in the neighbourhood of the emitter-base junction acts as base current which is amplified
   Found op http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=521-04-51
   
   
3. 
   phototransistor
   photoelectric detector that uses semiconductors in which the photoelectric effect is produced in the neighbourhood of a double p-n junction (p-n-p or n-p-n) which possesses amplification properties
   Found op http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=845-05-41
   
   

Tip: double click on a word to show its meaning.