ENGINEERING.com has updated it's forum.  To post a question please visit the new Ask@ Forum.   

With a database of over 10000 questions the library will remain available for an extended period.
Q&A


mohan		 Why does transistor BC107 have collector- emitter voltage drop=.3? View All


16 years ago - 2 weeks left to answer. - 1 response - Report Abuse
Respond to question
    0      [lnkReport]        0       0       
Share |
  Responses

phil
 That is a usual specification for VCE in the saturated region, usually labeled VCE(sat). typical is about 0.1 volts.

It's the way it operates. When you turn the transistor on with a base current, the collector saturates and the voltage goes to this low voltage (and low resistance) region. The base current has to be in excess of that required for linear operation.

Transistors have 3 main regions of operation. (1) Saturation, (2) cut-off, when the collector voltage will raise to the + supply and the current goes down to nanoamps, (3) linear, where it can operate as an amplifier, where the base current is at the correct value to hold the collector between Sat and cuttoff. It usually requires some sort of negative feedback to maintain this bias current.

Why? I'd have to go into the construction and theory of junction transistors. Don't really want to do that, try wikipedia if you need this.




For the 107, if you supplied 10 ma collector current (1.2k from 12 volts) and 0.5

16 years ago

Source:


  0     0         

ENGINEERING.com does not provide engineering advice. The Ask@ service is a forum for members to exchange ideas relating to the world of engineering. We caution users not to accept any responses that they receive without further validation, and not to rely on any engineering advice that they may get from other members of the Ask@ forum. ENGINEERING.com specifically disclaims any obligation to validate or verify any information posted within the Ask@ service. ENGINEERING.com encourages users to seek the services of a professional engineer for any engineering advice they may require.