Transistor electrical characteristic - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: July 26, 2016, 08:35:09 am
content: I checked a datasheet of a transistor and there are few characteristics I do not understandCollector-base breakdown voltageCollector-emitter breakdown voltageEmitter-base breakdown voltageCollector cut-off current ICBOCollector cut-off current ICEOEmitter cut-off current IEBOCan anyone please explain these voltages given above?Is Emitter-base breakdown voltage a minimal voltage that transistor needs to start working?

author: Kilrah
author_rank: Unknown
timestamp: July 26, 2016, 08:45:44 am
content: Breakdown voltage is the voltage at which something will start conducting even when it's not supposed to. A transistor is never supposed to let current flow between collector and base, but if you exceeded the collector-base breakdown voltage it couldn't hold it anymore.

author: Refrigerator
author_rank: Super Contributor
timestamp: July 26, 2016, 09:03:35 am
content: Collector-base breakdown voltage- Maximum voltage that can be between collector and base without damaging the transistor.Collector-emitter breakdown voltage- Maximum voltage that can be between collector and emitter without damaging the transistor.Emitter-base breakdown voltage- Maximum voltage that can be between emitter and base without damaging the transistor.Collector cut-off current ICBOCollector cut-off current ICEO- ( from google ) "Collector cutoff current is the IC that still flows when the specified VC and a specified reverse bias is applied. It is normally less than either ICEO or ICER (collector current with the base open, or with the base resistively connected to the emitter)."Emitter cut-off current IEBO- ( from google ) "emitter cutoff current, collector open (IEBO)The dc current into the emitter terminal when it is biased in the reverse direction with respect to the base terminal and the collector terminal is open-circuited. (Ref. IEEE Std 255.)"

author: PA4TIM
author_rank: Super Contributor
timestamp: July 26, 2016, 09:41:17 am
content: Download this book from tektronix. It is from the concepts series. It is about measuring semiconductors with a curvetracer but to do that you need to know all those parameters so they explain them allhttp://w140.com/tekwiki/images/a/a0/062-1009-00.pdfThere is a whole range of books in this series from the 60's and many of them are still very usable.http://w140.com/tekwiki/wiki/Concepts_SeriesAnd to add something often is misunderstood, hFEis not the same as hfe(for most it is written with a h and not a H) FE in capitals is the DC gain, fe is a bit more complex but in a nutshell you can see it as the small signal gain. The datasheet always states the hFEand sometimes hfe

author: Audioguru
author_rank: Super Contributor
timestamp: July 26, 2016, 12:42:23 pm
content: Did you notice that the datasheet said, "emitter-base breakdown voltage" but did not say base-emitter breakdown voltage? That is because a transistor base-emitter normally hasa forward bias voltageand it limits its own voltage to about 0.7V. The heating is low. If the emitter-base hasa reverse bias voltageof about 5V or more then it suddenly has avalanche breakdown and conducts as much current as it can like a zener diode and it becomes too hot causing damage.

author: madires
author_rank: Super Contributor
timestamp: July 26, 2016, 01:03:13 pm
content: Quote from: Refrigerator on July 26, 2016, 09:03:35 amComplicated names for leakage currentIt's very simple. The first two letters are the pins for which the leakage current is given, and the 'O' means the third pin is "open". Also the voltage applied to the pins is stated, like V_CE for I_CEO. I_CES is similar, but with the base shorted to the emitter, hence the 'S'.