1. adamzxtan

    Why did my transistor work?

    Hi guys, I designed a simple circuit here to use an Arduino Pro mini controlling a heater rod for my personal project. My heater rod is rated at 24V, 25W. I'm controlling the heater rod using a BJT transistor, FMMT617TA which is some leftover parts from my previous project. After I got my...
  2. cikalekli

    Input & Output Impedances of Common Emitter BJT Amplifier

    I want to study about "finding Input & Output Impedances of Common Emitter BJT Amplifier" However, I could not find a decent source & document about it. Could someone supply me with some documents for that. Then that would be gorgeous for my study. Thanks :)
  3. cikalekli

    Input and Output Impedance of the Common Emitter Amplifier

    Hi, I just have solved one of the bjt common emitter question below. However, I'm curious that how can I additionally find those things below: 1) Input and Output Impedance 2) AC Gain Here is the example and my hand draw solution. However, the question only asked to find Vout/Vin... Also, my...
  4. cikalekli

    BJT Common Emitter Large and Small Signal Research

    Hi, I want to study about BJT Common Emitter Large (or bias) and Small Amplifier Circuits. My question is I could not find a decent sufficient resource neither from youtube nor from google. :( I want to study about those common emitter large & small signal models, analysis, ac gain, input &...
  5. lsepolis123

    The 2N3904 in breadboard test for first time

    BJT practice in breadboard Bipolar transistors have three(3) poles, like The 2N3904 NPN Middle pole is base? The left/right poles are chosen arbitrarily,...? If No, how choose the collector? Ground (-) what should be, and what (+)...?
  6. jacob_c

    Why the ratio of Ic/Ib on BJT is not constant?

    Hi. The schematic of amplifier using BJT and the result is attached. What I learned is that the beta, ratio of Ic/Ib, would be constant. However, the ratio of Ic/Ib varies by the time. I googled for this and found out that the beta varies with temperature and Ic but does it vary that much...
  7. C

    Difference between SS8550, S8550 and 8550 BJT transistor

    What is the difference between SS8550, S8550 and 8550 BJT transistor? Are they equivalent or not and what does S denote?
  8. R

    What is Cmeu in an npn BJT operating in saturation mode ?

    I know Cmeu is parasitic capacitance in active mode. It's the B-C junction capacitance. But does it change when the npn is operating in saturation mode? Also in general(not just in saturation mode) what happens to Cmeu at increasing Vce? Does it increase? What other things happen to the...
  9. R

    Do we select a large or small BJT to amplify high frequency response?

    Part of me thinks we need a smaller BJT, to reduce base emitter junction area. but I am confused
  10. M

    NPN BJT Emitter Follower - supply at Collector Current (Ic).?

    Greetings everyone, I am planning to design a current amplifier using an NPN BJT Transistor with an Emitter Follower configuration. On top of that, instead of using batteries, I am using 2 separate LDO voltage outputs as the input voltage(Vin/Vbb) to the BJT as well as the supply voltage...