That actually makes complete sense! :-) So I'm fine to use a 3-pin version in a circuit that would normally use a 2-pin version...as long as I leave base N/C? -marc On 8/7/03 08:47, "Michael Rigby-Jones" wrote: >> -----Original Message----- >> From: Marc Nicholas [SMTP:marc@GEEKYTHINGS.COM] >> Sent: Tuesday, July 08, 2003 1:39 PM >> To: PICLIST@MITVMA.MIT.EDU >> Subject: [EE]: Phototransistors (*holding my head in shame*) >> >> This is probably a really, really dumb question...and probably a result of >> my lack of formal electronics education ;-) >> >> Why do three pin phototransistors exist? Is it purely for >> aesthetics/standardized packaging reasons, or is there some intrinsic, >> magical reason I'm missing? >> >> -marc >> > For biasing to improve either sensitivity or speed. Phototransistors used > without any base connection are very slow. By providing a dc path from the > base, the charge in the BE junction can be removed more quickly, speeding up > the transistor at the cost of reducing sensitivity. > > Mike > > > ======================================================================= > This e-mail is intended for the person it is addressed to only. The > information contained in it may be confidential and/or protected by > law. If you are not the intended recipient of this message, you must > not make any use of this information, or copy or show it to any > person. Please contact us immediately to tell us that you have > received this e-mail, and return the original to us. Any use, > forwarding, printing or copying of this message is strictly prohibited. > No part of this message can be considered a request for goods or > services. > ======================================================================= > Any questions about Bookham's E-Mail service should be directed to > postmaster@bookham.com. > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -------------------------------------------------- Marc Nicholas Geekythings Inc. C/416.543.4896 UNIX, Database, Security and Networking Consulting -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.