Munky Posted March 25, 2006 Report Share Posted March 25, 2006 how does NPN transistor works? Quote Link to comment Share on other sites More sharing options...
logan_dslasher Posted March 26, 2006 Report Share Posted March 26, 2006 http://www.satcure-focus.com/tutor/page4.htmhttp://www.physlink.com/Education/AskExperts/ae430.cfmHi Munky!sorry i can't provide you with my own explanation.. try those links.. hope they help you.. if you need more explanation, google it up! im sure you'll find some simple explanations there.. GOod luck!BTW, Welcome to eLab! ;D 8) Quote Link to comment Share on other sites More sharing options...
helio905 Posted April 3, 2006 Report Share Posted April 3, 2006 A npn transistor works jus like a silinode. Imagine the base being the silinoideactivator and the collector is the hot wire and the emiter is the part that getconnected when the silinoide gets turned on. The Base also controls the amount of power that is allowed to pass through. Quote Link to comment Share on other sites More sharing options...
auto-silicon Posted May 21, 2006 Report Share Posted May 21, 2006 I think, In amplifiers the NPN Transistors work on the negative frequencies and the PNP transistors work on the Postive Frequencies, this is only an example used in amplifiers though. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 21, 2006 Report Share Posted May 21, 2006 I think, In amplifiers the NPN Transistors work on the negative frequencies and the PNP transistors work on the Postive Frequencies, this is only an example used in amplifiers though.Nope.All transistors in an amplifier amplify all frequencies. Frequencies don't have polarity.If the amplifier has a complimentary class AB push-pull output and has a positive and a negative supply, then the NPN is an emitter-follower for the positive output voltage swing and the PNP is an emitter-follower for the negative output voltage swing. Quote Link to comment Share on other sites More sharing options...
auto-silicon Posted May 21, 2006 Report Share Posted May 21, 2006 That's what it was, i forgot.Thanks Quote Link to comment Share on other sites More sharing options...
indulis Posted May 24, 2006 Report Share Posted May 24, 2006 To understand how "they" work, you really need to understand semi-conductor physics including electron bonding at the atomic level. Once you get "that stuff down", terms like... doping levels, majority and minority carriers, etc. will make a bit more sense and you'll know exactly how they work. Quote Link to comment Share on other sites More sharing options...
slackjack Posted May 24, 2006 Report Share Posted May 24, 2006 Here is a brief intro to semi-conductor physics I uploaded some time ago.http://www.electronics-lab.com/forum/index.php?topic=6168.42 Quote Link to comment Share on other sites More sharing options...
princestephenranji Posted June 1, 2006 Report Share Posted June 1, 2006 A NPN transistor works on the basis of semiconductor theory ie current given to the emitter (N Region) is the sum of base current (P Region)+collector current(N Region).in power mode use of NPN transistor when the base gets +ve voltage(low current) -ve voltage from emitter jumps to collector.In amplifying mode signals feed in emiitor-base region jumps to collector-base region if we include a battery source in collector circuit we can get an amplified output. Quote Link to comment Share on other sites More sharing options...
indulis Posted June 3, 2006 Report Share Posted June 3, 2006 ...in power mode use of NPN transistor when the base gets +ve voltage(low current) -ve voltage from emitter jumps to collector.In amplifying mode signals feed in emiitor-base region jumps to collector-base region...Voltages "jump"???? While electrons may "jump" from valence to valence, can you please explain the theory of "-ve voltage jumping" from emitter to collector??? Quote Link to comment Share on other sites More sharing options...
princestephenranji Posted June 3, 2006 Report Share Posted June 3, 2006 Sorry physics sir,i am only a student also do not know much about transistor theory.But in practical use of transistor no one thinks of theory.I just used the term 'jump' just to explain its working for practical circuit designing,a simple example is switching a relay 'on' using npn transistor in conjunction with IC MCT2E.('+'ve voltage from IC MCT2E is feed to base of npn transistor and '-'ve voltage from emittor of npn get transferred to collector which then powers the relay). Quote Link to comment Share on other sites More sharing options...
indulis Posted June 4, 2006 Report Share Posted June 4, 2006 Here is one way to look at transistors..........Consider a large, tall water tower with a faucet on the side. For a NPN, the water tower is the collector voltage the faucet handle is the base, and the what comes out of the faucet is the emitter. The more you open the faucet (provide more base current) the more comes out (emitter current). Also, the more you open the faucet the lower the pressure differential between faucet inlet and outlet (lower Vce sat). If the water tower side pressure becomes too high, the faucet will fail (collecter voltage to high and transistor goes up in smoke)... etc. etc. Quote Link to comment Share on other sites More sharing options...
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