Read about transistor | 50 Discussions | Page 1

  1. Boltzman Oscillation

    Are ISFETS available for cheap or am I out of luck

    I was looking into measuring the ph levels of a lake nearby where I live. I wanted to tie the experiment to my electronics coursework so I did some reasearch and found the wonder electronic that is the ISFET. Unfortunately, I cannot find anywhere to buy an ISFET transistor; I can easily find...
  2. P

    Transformer Coupled Class A amplifier Single supply

    How can Vce vary from 0 to 2Vcc? In class, I learned that it was due to Lenz Law working in the transformer and a voltage of Vcc being induced to reverse the change in Ic. However, I cannot picture this. Can someone please explain with a diagram of how this comes about in the transformer windings.
  3. K

    How to select a transistor?

    Say you want to choose a npn transistor which works for 1000V and 4mA (Peak inductance current is around 1A) in the collector side while emitter is grounded. Which parameters should I look into to select a suitable transistor ? for the voltage should I be looking into Vbe ? or is Vce enough ...
  4. B

    How to calculate Carrier Concentration vs. Depth from a CV measurement?

    I'm trying to obtain the free carrier concentration vs depth profile from the CV (capacitance-voltage) measurements of a normally-on HEMT with the expressions used for a Schottky barrier, but I´'m confused about how to extract the values for depth. I found in textbooks and articles that the...
  5. Peter Alexander

    Engineering Compute the voltage gain of this bipolar junction transistor circuit

    This is the given schematic. The result should be $$A_u = \frac{R_b g_{21}}{1 + R_b g_{22}} = -50$$ and the way I wanted to tackle this problem is by stating $$A_u = \frac{-R_b i_2}{u_1} = \frac{-R_b (g_{21} u_1 + g_{22} u_2)}{u_1} = \frac{-R_b (g_{21} u_1 + g_{22} u_2)}{g_{11} u_1 + g_{12} u_2}...
  6. C

    Class A Amplifier Sinusoidal Input/Output Relation

    My simplistic derivation below for a Class A amplifier shows that an AC signal at the input produces DC, fundamental, and 2nd harmonic terms at the output. This seems to contradict most the information I have found on this - which just states that the output is sinusoidal and of the same...
  7. Zeynel

    I Transistors and Quantum Physics

    My question is: What is the contribution of Quantum Physics to the discovery, of the transistor? In Adam Becker's book What is real? I read that, "the discovery of quantum physics in the early twentieth century led directly to the [discovery] of silicon transistors..." He implies that, the...
  8. Peter Alexander

    Engineering Computing resistance in given circuit with BJT

    Hi, before you proceed with reading this question, I would like you to know what I do not expect anyone to solve this task for me. I have a problem with a single step in the solution and I'm only asking you to help me with this one step. 1. Homework Statement Compute ##R_B## so that Q-point of...
  9. A

    Voltage Gain of a common-emitter amplifier

    Hi, i have a problem with the voltage-gain of a common-emitter-amplifier. I have calculated the theoretical value of the gain given by ##G=\frac{\partial U_{a}}{\partial U_{e} } = -h_{FE} \frac{R_{c} }{R_{v} }## , which is between -13925 and -7311 for ##420\leq h_{FE} \leq 800## (given by the...
  10. Delta2

    Ohmic Resistance and Logic gates

    Is ohmic resistance a "necessary evil" in order for transistors to be able to function as logic gates? I mean, I have seen some circuits for the NAND gate in RTL and TTL and they both seem to involve ohmic resistances. Can we make a super conducting NAND gate that will have total ohmic...
  11. D

    Finding the CMOS transistor width ratio

    Homework Statement Calculate the ration of ##w_p/w_n## if n and p transistors in CMOS inverter necessary for the least delay time ##t_p## if the circuit is used in a chain of circuits. a) What is ##w_p## in that circuit if you're given : b) Calculate the maximum short circuit current if...
  12. Voq

    End of Moore's law?

    What are indications for future development of transistors and general computing technology design with the Moore's law in mind? Are we going to redesign architecture for better efficiency and what future brings?
  13. A

    Simulation of transistor switch circuit

    Hello, I'm new to electronics and I'm reading a book currently to learn more about the topic. I'm currently on a section where I'm building circuits where I'm using a transistor as a switch. I decided to experiment with the circuit they gave me and put it in a simulation software called Proteus...
  14. Voq

    Transistor literature (books, links, articles) for learning more about them...

    If you have any material (books, links, articles) on transistors i would appreciate that. I am looking for a way to get more general knowledge on subject. Thank you.
  15. A

    Bizarre Behavior in Discrete PMOS

    Some of my colleagues and I captured the i_D vs V_ds/V_sd curves for the CD4007 MOSFET IC ( We did this for the NMOS and PMOS transistors. I have attached the curves to this post. The NMOS curve is as expected. However, the PMOS curve seems to be...
  16. OldWorldBlues

    Trouble understanding common-emitter amplifiers

    Hi there! I've been tinkering with some homemade speakers, and wanted to make a simple amplifier circuit to step up the some 3 volts that comes out of an aux jack to 9 or 10 volts. I decided that the common-emitter model looked the easiest to understand. I was mistaken. This is the simplest...
  17. S

    I Straight line plot of bipolar transistor - temperature?

    Hey everyone, I'm trying to plot a straight line for a bipolar junction transistor to find the room temperature, T, using my experimental results for the associated base-emitter voltage, ##{V}_{BE}## and collector current, ##I_C##. Here's the equation that I'm using: $$ I_C = α_F {I}_{EO}...
  18. M

    Question about circuits with transistors (current, voltage)

    Homework Statement 1. In Figure A-1 of Experiment 18, assume that Vdc = 8Volts, R1 = 1kOhms, R3 = 7kOhms and there is no R2 resistor. Determine the current in R1 when the transistor is fully on and carrying current. Express your answer in mA. 2. In the circuit of Figure A-1, Experiment 18...
  19. Cocoleia

    Transistors and Beta

    Homework Statement I have this circuit Where I have to find R given that I=2mA, and Beta =200 Homework Equations Ic=Beta Ib Ie = Ic+Ib The Attempt at a Solution I would have thought that the voltage Vb would be -9.3V, since we have Vbe = 0.7 and at the bottom we are given -10V. Then I would...
  20. H

    Increase the maximum voltage rating of semiconducter

    Hello, I was wondering if there is any way of increasing a transistor or thyristor maximum voltage ratting in DC? Thanks. Edit: Just to be more precise, I am referring to the off state. I know you can the on state via a resistor.
  21. V

    PNP Transistor voltage calculation

    For the B) part, I don't get why is it that for calculating voltage between collector an the emitter (Vce) I take into account diode on base (0.7V), whereas for part A) it's ignored? Why is Vce in part A and part B are calculated differently? Why is it that in part A voltage of 0.7V isn't taken...
  22. Cocoleia

    BJT and MOSFET complete analysis

    Homework Statement I have been given the world's longest transistor problem as an assignment :wink: Here is the circuit: I am asked to find: a) V1, V2 and V3 using DC analysis b) AC equivalent circuit c) AC tension gain: Ava=Vx/Vsig d) AC tension gain: Avb=Vo/Vx e) Total AC tension gain...
  23. K

    Calculating the amplification of a transistor

    Homework Statement In the circuit shown below, I have to find the amplification for when the commutator which connects to the 4 kΩ resistance is open, respectively closed. We know the Beta factor to be 200, and the current through the base is negligible. The transistor is made of silicone...
  24. srinaath

    Electrical DIY wireless power transfer device concept

    i am planning to do a small diy wireless power transfer device. The circuit of the transmitter is receiver has just the coil and load arrangement. my query is, (please correct me if am wrong) -->to induce a voltage in the secondary coil, there must be a varying magnetic field right? -->but...
  25. MarcusAu314

    BJT transistor analysis: common emitter confusion

    Recently I started studying semiconductors and analogue electronics. First I studied the diode and its I-V characteristics and analysis in DC circuits, as well as in AC circuits. Now I started with BJT transistors. I was explained that transistors act as electronic switches. My problem is not...
  26. LalaDeil

    I'm looking for this transistor

    Hi, I need this transistor, but I have no more references than this number.
  27. 1rel

    NPN BJT transistor: base voltage / emitter current

    I don't know how to calculate the voltages at the bases of every transistor shown in the lower row of that picture (~3V (2.9..V), ~2V, ~1.8V). Any help would be appreciated! - I'm currently trying to figure that out... The other thing I don't really understand: Why do the transistors in the...

    Capacitive touchscreen control using a transistor

    Hello, I'm posting the first time on this forum. I want to create a robot controlled by an Arduino which is able to make a touch signal without using a mechanic arm or finger ( here is a robot with the same goal but using an arm video). I want to take the electrical approach. A modern...
  29. Adrian Collings

    Why is my transistor overheating?

    Okay so I am having this problem with a transistor overheating in a motor control circuit and I am not exactly sure why it is overheating. There is a PWM signal being used to power the transistor from an MSP430 microcontroller. I am using a standard 1N004 kickback diode for the motor and an...
  30. Y

    Classical Understanding transistors

    I am having troubles understanding the working of a bipolar junction transistor(and also its uses as switch, amplifier, oscillator etc.). Can anyone recommend any good book or video explaining it?