Bjt Definition and 216 Threads

  1. A

    How Do BJT Transistor Characteristics Relate to Their Construction?

    Homework Statement hello guys I have an assignment to "Explain six transistor characteristic curves using the construction and operation of BJTs" I searched all over internet but couldn't find any article relevant.(i found lot of articles about characteristic curves but none of them...
  2. M

    Urgent BJT Current Issue Help: Understanding Passive Sign Convention

    BJT current issue help urgent hello i have a problem with current and the convention and so on. bottom line for a bjt my professor said that Ie = Ic + Ib but the next slide he remixes it telling us that and i quote " the relatively large current flowing from the emitter to the collector is...
  3. A

    What is the physical origin of gain in a BJT?

    Homework Statement "What is the physical origin of gain in a BJT?" I can figure out gain using gain equations but am having a hard time describing the physical origin of gain in a BJT.. can anyone help?
  4. D

    Help on BJT Q1: Calculate DC Input Resistance w/ Current Gain of 400

    Please view the attached circuit. I will be appreciated for any suggested answer, thanks! Q1) Calculate the dc input resistance of the transistor amplifier shown in figure 1 below if the current gain of the transistor is 400: I need some help on this one, i don't know the relationship...
  5. P

    BJT amplifier frequency response.

    Today I did a lab on BJT amplifier frequency response. I got the fc1 and fc2,BW and F0 center frequency. The band pass turned out to be asymmetrical. What i want to know is this. Input V=40mVpp output V=2Vpp cut off V=1.41Vpp When I turned up the frequency to 2fc2, i got about...
  6. N

    A bit confused about BJT charge flow

    In this picture, as well as countless others: http://en.wikipedia.org/wiki/Image:NPN_BJT_Basic_Operation_%28Active%29.svg we have electrons flowing from emitter to base, and 'holes' from base to emitter. Why the distinction? When an electron flows from emitter to base, is it not the...
  7. A

    Low Voltage BJT: Why 0.225V - 75mV?

    i want to know why at some point the low output voltage for a bjt biased between 0 and 5 on the base and voltage 5 at the drain ranges between 0.225v and 75mv so which of them is the low voltage pz answer me now i have a project to deliver
  8. N

    BJT: common-base amp; moving-coil microphones/preamps

    I was researching a bit about the common-base configuration of a BJT transistor on wikipedia, and I found this quote: "This arrangement is not used as much as other configurations in low frequency circuits but is often employed for amplifiers that require an unusually low input impedance, for...
  9. S

    Working of BJT as an amplifier: concept

    How does a small change in base current result in a large change in collector current in a BJT? Please explain in terms of movement of electrons (in NPN). Most textbooks I have referred say that the reason is low resistance of emitter-base and high resistance of collecter-base. However i cannot...
  10. N

    Engineering BJT Biasing Circuits: Compare Advantages, Uses & Benefits

    We've base biased circuit, voltage divider, emitter bias, and collector feed back bias...I'm looking for resources, to compare those 4 types, what are the advantages of each type, why is it used, and where... I know BJT's work in amplifiers, but i need more detail concerning those different...
  11. D

    Designing Audio Amplifier with BJT and MOSFET Components

    Hi, I'm new here. can somebody put here an a schematic of Class AB, D,G or T. I need an audio amplifier that work with bjt and mosfet simultaneously, i think that kind of amplifier is class g, but I'm not sure,for example i saw an 5000w amplifier with 2sc5200 and his pnp pair working with...
  12. A

    What Constitutes the Base Recombination Current in a PNP BJT?

    I thought that the base recombination current (say in a pnp bjt) was the current caused by the electrons that come up the base wire to compensate the loss of free electrons from the recombination process in the base. But recently I read that this are actually two different currents that sum up...
  13. A

    How do resistor values affect the operation of a BJT transistor?

    I'm really confused between saturation and amplifier. When will the transistor work in saturation mode and in amplifying mode? Resistors are the matters. We chose the resistors so that the transistor will work in saturation or amplifying. How can we chose?
  14. A

    About Using transistor BJT as a switch

    In order to use BJT as a switch, it's very popular to do as the picture. In the picture, V_B > V_E, so there's a current flow I_BE control the I_CE. In the other way, V_B > V_E generates the current I_CE, and the lamp will light on. But, I change the connection a little: I'll let the V_B...
  15. K

    Implementing Phase Shifter with BJT

    Can anybody explain to me what and how a phase shifter can be implemented using BJT.or give me the site which can get more details about this.
  16. C

    How Does Collector Current Affect an LED in a BJT Transistor Switch Circuit?

    Hi, I know how to drive a transistor as a switch, but I am not very sure how to perform voltage and current calculation and analysis at the collector to emitter side. Basically what I know is that if the base is biased at 0.7 V, the transistor will be switched ON and current will flow...
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