Transistor Definition and 508 Threads

I want to amplify the current/voltage from a music source. Specifically, I want to use the varying signal to vary the light intensity of a system of LED's connected in parallel. Basically, I want to create pulsating LED's. What I'd thought of was using a sound signal from my ipod to do so. I...

Here is the problem: The PMOS transistor in the figure is conducting current. (a) Is V_TP > 0 or V_TP < 0 for this transistor? (b) Based on the value of V_TP, what type of transistor is in the circuit? (c) Is the proper symbol used in this circuit for this transistor? (d) If the symbol...

Just curious. For some odd reason, I don't seem to get it.

what is the impact of the temperature on the characteristics of NMOS transistors?

what base-emitter voltage is needed for a current to flow through the trasnsistor?

I use my computer a lot for watching movies and at night i really don't like getting up and having to manually hit the power switch, so i was thinking it could be possible to do it wireless. Now i have a general concept here, maybe an IR reciever going to the base, a line feeding from...

Greetings Can somebody please help me understand the use of transistor as a switch and that as an amplifier?

What's about this? Where a capacitor is between base and collector (NPN). I have formulated some of my own theories (it seems like this is totally unknown of on the internet, and the books I've looked at don't explain it), but I have thought of flaws to all my theories. Can anyone please...

Homework Statement an npn transistor is used to drive a constant current I through three ‘white’ LEDs, connected in series. If the required current value is I = 25 mA, and the current-gain of the transistor is β = 300, find the value of the resistor R, giving your answer to 3 significant...

Alright, I've been stuck on this problem for my electronics class for far too long. " Design a CE amplifier with a gain of 10 using a 2n3906 transistor and a 20 V power supply. Calculate the required resistor and capacitor values for the circuit, assuming a minimum frequency of 10 Hz." It...

Hi guys, I need to build a REALLY simple amp for a friend. I only want to use a resistor and a transistor plus the normal stuff(battery and speaker). Please help. Thanks in advance, Circuit Man

Homework Statement Consider a PNP Biploar Junction Transistor uniformly doped in each region. Sketch the energy ban ddiagram for the case when the transistor is biased in a)In thermal equilibrium b)biased in the active region c)biased in the cutoff (depletion) region Homework...

Hi, Could someone please help me with something i need to know to complete my college course? The question says: 'Show with the aid of a circuit diagram and input/output waveforms how and NPN transistor can be used as a small signal amplifier, when operating in a common emitter...

i don't understand the difference between low ,high,midfrequency analysis of transistor amplifiers...what's midband analysis?

I'm trying to create a simple power supply for a project, but it's not working correctly. I have a reference voltage (4.1V) and a supply voltage (4.8-5.0V). My goal is to connect an opamp functioning as a voltage follower with a transistor used to supply the adequate current. That is a...

http://www.vcaa.vic.edu.au/vce/studies/physics/pastexams/physicspilot12004.pdf Page 13. AC signal on CRO. Answer is B. How the heck do they do that? Relevant information is on page before. Love peoples explanations but please try to keep it simple. Sorry if i seem direct. I don't...

My year 12 exams are in 1 week exactly and I'm worried about a question (from last year's exam) that my teacher can't even answer. Each year they tend to repeat the difficult questions, and this was one of those. I'll just give a summary of the question, and maybe you'll be able to answer my...

Hey... I really want to know the root means. I mean i know how a transistor works as in how it functions... But I don't know how it works that way, I want to know the "physics" meaning... as in why it works that for all the various transistors and other components. If someone has a link as to...

Hi, I've been learning about transistors lately through the Horowitz & Hill book. I'm surprised to see that when used as a current source the collector voltage only changes with load voltage with an ideal transistor. When I say I'm surprised I mean that in non-ideal models the base current...

Hi All, The question I ask is pretty elementary.Come to think of it, i am not even an academic and the industry I work in is different. The BETA of a transistor. What is it in physical terms. How do the manufacturers of the transistor decide how to put that beta into it,physically.Does it depend...

Hi, I'm having a bit of trouble understanding how exactly to analyze a transistor in a simple circuit... Specifically when finding the collector to emitter voltage, Vce. I've got to be looking at this incorrectly. Below is the question and the solution. My professor worked out the part...

I have an amplifier circuit as shown in this picture, http://www.fileden.com/files/2006/8/19/175303/4.wmf" And I need to do a DC analysis on it to find the current into the base lead (I_B) and the voltage over the collector-emitter (V_CE). Realizing this is DC and that the capacitor will...

This is more of a "help me understand" than "help me find the answer" problem. forgive me for not using the template. this is the "little r-e" model, similar to the hybrid model I'm having a bit of trouble understanding how my professor got the equations for these two examples...

here's some newb questions for ya: if you apply an AC signal to the base of a transistor (DC sources and coupling capacitors all included in the circuit to treat it like an amplifier), and on your output (Vce in this case) you get clipping on the negative side of your sinusoidal waveform...

Homework Statement Assume the circuit pictured below: http://img259.imageshack.us/img259/3443/problem2bwz3.jpg The transistor follows these rules: I_D\,=\,0 if V_{GS}\,\le\,V_T I_D\,=\,g_m\,\left(V_{GS}\,-\,V_T\right)\,\left(\frac{V_{DS}}{V_{DS, SAT}}\right) if V_{GS}\,\ge\,V_T\, and...

Homework Statement Find the Thevenin equivalent at terminals a-b for the transistor model below. http://img254.imageshack.us/img254/7228/chapter4problem52bj6.jpg Homework Equations KVL, KCL, v = i R, R_{TH}\,=\,\frac{V_0}{I_0}The Attempt at a Solution I took out the independent voltage...

I have a problem of calculating the current through a system. It is a simple JFET transistor with the source grounded. The gate is reverse biased with a 3v potential, and the drain has a 2000 ohm resistor in series then a positive 20v potential in series which is of course grounded. How would I...

Hi, I have to do a brief introduction for transistors in my seminar class. Are there any simple demos you recommend? it's just to show the class what a transistor does? we were thinking about activating a LED. any other options (we wil be using a breadboard) thanks!

http://www.brokendream.net/xh4/circDiag.png We're given this diagram with a question and asked: (NPN transistor) a) Describe what would happen when the circuit is switched on. b) Explain why this happens. c) What is the time constant for the capacitor in this circuit? d) What is the purpose...

need help understanding the transistor circuit of a Boolean "NOT gate" can some one please link or upload a scheme or would this one i attached work? and how do you display in which direction the current flows? that's what I'm trying to show with the battery halves...

Why is the breakdown voltage higher if the transistor is weakly doped? My intuition says that if the base and collector are weakly doped, the width of the depletion region will be bigger, so the number of extracted electrons/holes will increase, and so will the probability of ionisation by...

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...

Hi, Does anyone have any good resources on CE transistor amplifiers? Preferably ppt presentations or something... I've done the preceding questions, but i can't do 30a... How would i go about doing it? Thanks

Ok so i recently actually learned what transistors due, when used as amplifiers (i always knew they acted as sort of switches). now my question is...how does this happen? Is it true that if i hooked up a 9v battery to the input side (lets say it puts out .1A due to resistance in the transistor...

Hi all. I'm currently writing a report on a tuned transistor circuit. I'm supposed to find a Q value for it but I'm a tad overwhelmed. My lecturers splurged out a heap of formula in my direction. I can't make any sense of it. From what I understand, I should be able to find the Q factor from...

Hi all :) I need some help with the concept of parasitic capacitance. I'm currently doing some analysis on a basic tuned transistor circuit. I know the LCR portion of the circuit is there to remove parasitic capacitance. The only problem I'm having is I don't exactly know what parasitic...

Hey guys, Right now I have a circuit designed and seems to work fairly well. Now the output from my circuit is a negative output and I need it to drive a relay. The relay I am using says it draws about 100mA and my chip will output 50mA max. I figured I would put a transistor on the output...

What is the difference between a current source using an op amp and one using a single transistor? Why would you use one over the other, etc? Thanks!

I have the amplifier in the attached file and I measured Vout without any input and got a really big number. Should it be really big or really small? I mean theoretically, what should it be equal to because I'm not sure that my answer makes any sense. Thanks!

Hi can anyone explain to me how you can drive a transistor to function as a switch?what calculations i have to make in order to decide the type of transistor that i need and the kind of resistors that i need. also i have a voltage of maximum 80 mv.i want to enlarge it in order to drive the...

hi i want to use a microphone connected to the base of a transistor.yhe transistor should work as a switch . it should turn on with a sound to the micro phone. does anyone know what voltage the mic can produce?what kind of microphone do i need and what kind of transistor?the circuit is designed...

Hi guys, i want to fix a circuit that will use a led and i want to use a transistor as the switch to the led. I would like the base current to be produced by a sound played throug ha mobile. A sound turning the light on and the same or other sound turning it off. No ideas how to do it.Thank you...

Hello all, I haver a circuit design problem that is giving me grief. The problem basically asks to use a circuit with a BJT transistor to drive an LED with a certain maximum current. Thus, the BJT needs to behave as a voltage controlled current source, the prof hinted that the design should...

Hi, I'm doing research to chipproduction, and I can't seem to figure out how transistors really work (in detail). I'm looking at this CMOS inverter gate for example: http://people.deas.harvard.edu/~jones/es154/assigns/prob_assign_01/prob_assign_5_01/cmos_1.gif More detailed...

OK, I need some help here. I can´t really recognize the type of transistor configuration on a circuit (common emitter, common base, common colector). I`ll some tips that help me identify the configuration. Check the circuit attached.

Hi guys! Need some help. Attached is a circuit that I designed. The Vin is 7.2V and the Vout (at the load) is 5V. Basically, that's exactly what I wanted! Anyway - can someone please help me with the understanding of the circuit. I know the basics but I'm a bit stumped on the use of the...

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...

hi, could anyone pls tell me why the storage time of a transistor changes as u change the position of one resistor? During an experiment, when the resistor connected to the base voltage was reconnected to the ground i noticed that the storage time increased. pls someone explain to me why...

:rolleyes: hi, could anyone pls tell me why the storage time of a transistor changes as u change the position of one resistor? During an experiment, when the resistor connected to the base voltage was reconnected to the ground i noticed that the storage time increased. pls someone explain to...

Is there an IC that has 2N3904 transitor in it? I have to use an IC instead of transistors so I was wondering what is it's IC equivalent? :confused: Tnx.