Transistors Definition and 143 Threads

Homework Statement When I measure CB ciruit: I have got these results: And here CE: Homework Equations The Attempt at a Solution So.. here is table, how to calculate h parameters: But I don't understand, am I using it correctly. When I use results of my table...

1) While plotting input characteristics of a transistor, we choose to keep output voltage constant and plot the variation of input voltage and current. Why do we choose to keep output voltage constant and not current? 2) While plotting output characteristics of a transistor, we choose to keep...

About the stages of a transistor.. Active,Saturation and Cutoff. Active its obviously on and cutoff off. May be a dumb question but is the transistor ON on Saturation mode? Also my textbooks says that when the BE junction is forward bias, Vbe= 0.7V. But at the same time in another problem it...

Homework Statement Given the configuration below http://img844.imageshack.us/img844/3364/c5e8.png Find A_{V} and A_{I} Homework Equations The Attempt at a Solution I start off by drawing the small signal equivalent r_{e} model. http://imageshack.us/a/img268/7201/9e.png I start off by...

Hi everyone, at my university (Computer engineering) we are studying the small signal model, but i didn't understand the practical application, i mean, why and when should it be used ? For example at home i usually make electronics circuits, so i wanted to know how can i use the small signal...

Hello everyone, can anyone please suggest a good book on the theory of transistors. I want to study transistors from more of physics point of view i.e. how they actually work internally. Thanks in advance.

Hello, I've been playing with transistors on a circuit simulator and found that it doesn't matter on an NPN transistor whether I put the load on the collector or emitter side, the load still has the same current flowing through it. The same is true for the PNP transistor, however when I...

Devices today are getting smaller and smaller which makes the circuit layouts more complicated and hard to design. And knowing that microelectronics is just limited to the size of the atoms. Are people today now developing a replacement on transistors? Just like in the past when they are...

From what I understand, transistors can be viewed as several things, one of which is a resistor. So how much resistance is a transistor turned on generally equivalent to? And what is normally considered a large or small resistance? I know voltmeters have a large internal resistance in...

How do I know if a transistor is voltage controlled or current controlled? It seems to me that changing voltage, ceteris paribus, changes the current so what gives? http://en.wikipedia.org/wiki/Bipolar_junction_transistor#Active-mode_NPN_transistors_in_circuits Talking about exponential...

...outside integrated circuits? Can OpAmp's replace them?

Hi. If I could get some clarification on the attached circuits that would be great. The question asks to find the boolean expression for C. I already know the answers, but I don't quite see how they got it. For the first circuit: C=A_bar The truth table looks like this: A C 0 1 1 0...

I am going to give a presentation on High Electron Mobility Transistors (the ones that use a 2 dimension electron or hole gas), and although I can find many detailed descriptions of the band structures and what causes the 2DEG's high mobility, I haven't found a clear description of the process...

South Korean researchers have developed a magnetic transistor switch which may save power: http://www.nature.com/news/magnetic-logic-makes-for-mutable-chips-1.12321 I'm wondering if this could benefit space applications, but on more than just power-saving. Magnetic states aren't as...

Hi All, I've been reading about tunnel field-effect transistors (TFET) as a potential design to impact post-CMOS technologies, however I'm having a hard time understanding the idea and also some of the terminology. For example, what is a p-i-n TFET? I understand that one side has to be...

In particular, I am looking at a datasheet of a PNP BJT: http://www.fairchildsemi.com/ds/2N/2N3906.pdf I noticed that in the ON CHARACTERISTICS sub-heading, there were multiple h_{FE} values. I'm wondering how I could extract any meaningful information from that since the most common h_{FE}...

Hello, I have a transistor (BC547B) that is being used as a switch, connected to the base I have an 9v battery and an LDR with a maximum resistance of 1m ohms. However this is still not enough not to switch off the transistor. Can someone tell me how I can work out what resistors I need, so the...

hello all, i need some help on this one. i want to do an article about the posible aplications of quantum entanglement in aircraft flight control systems. i want to entangle two transistors, put one of them at the ACE - actuator control electronics (probably) in the pilot's cabin and the other...

does that mean there are trillions of connections to each transistor that connect to various other parts of the board? how does that work? how is the signal from one transistor distinguished from another transistor right next to it on the microprocessor?

This thing just popped into my head last night while describing to a friend, possible end of our universe. Which one is higher? the number of stars in our universe or the number of MOSFETs we mass-fabricated in our civilization ? My guess is though number of stars. What do you think...

Hello, I have cool idea for a device and one hardest part of it is to detect the movement of the object. I think I can use a wire coil, and a small magnet attached to the moving object. When the object passes the wire coil (up or down), there will be small voltage inside the wire coil. It...

Hello all I have a fairly straight forward question about transistors. I am an engineer focusing in power generation systems, and currently working on designing a test inverter for a new type of DC generator. I have extensive knowledge of DC circuits and power systems, however this is my first...

Using a BJT transistor as an example, can current from the power supply only travel from the collector to the emitter when the transistor is on or can it travel in the reverse direction if the polarity of the DC power supply is reversed?

Homework Statement Hello everybody, I have a problem dealing with complex circuits, especially those that have extra symbols (transistors, earth, V_in, V_out). Hopefully somebody can give me helping hand. Thanks a bunch. This is the link to the problem which is on page 11 (the first one)...

Why is it required to have 6 transistors? Can it not have 4? Can the output not receive two LOW signals at once? Or does it have something to do with superposition such that upon adding the two signals it may enter the noise margin? Here, I added a photo.

Hello. In a class today, the lecturer said, in an introduction to the material that will be covered, something along the lines of "..and the current is kept relatively flat (low?) thanks to impedance ..." Is this because impedance acts like resistance (but in AC circuits), or would there be...

Hello Forum, question about BJT transistors: some books say that they are current (base current) operated... Some other books state that the emitter-collector current is controlled by the voltage between the base and the emitter...which one is correct? FET are voltage controlled... Holes...

Hi, I've been busy in designing some circuits and I want to simulate some non linear behavior of transistors and diode circuits. I want to find a free simulation program. Does LT Spice work on these discrete components? Thanks Alan

Hi, I'm a newbie... I came to know that there are many types of transistors available in the market with high, middle, and low β values.But, I don't have any idea about applications of each in detail.Can anybody tell me the applications of high β, middle β, and low β valued CE...

I thought I had a good understanding of transistors, but I have seen articles on how to tell the collector from the emitter. I had always pictured transistors as a perfectly symmetrical device. Either side could be the collector, and the opposite side was the emitter. Clearly, there is some...

Hi, I'd need some help regarding some parts of an exercise (attached below). The question is that they make me assume that the tranistors is working as a chopper, so then I have many things to calculate. The question is, which kind of chopper should I assume? Thanks in advance...

Are transistors essentially diodes with a perk? I mean, they do exactly what diodes do (one way valves) AND they can amplify current. Doesn't that make them more efficient? Why not make only transistors then? They appear to be always made out of the same basic materials, so I don't see the big...

Homework Statement Given the following transistoric circuit. The transistor acts in the active region. In addition: VBB = 0.6V http://img855.imageshack.us/img855/9901/newcircuit.jpg The Attempt at a Solution Before I get there I have two questions: 1) What does it mean that the transistor...

I'm just looking over some introductory notes to transistors and it says that BJT transistors are useful for amplifying current, so does this mean that power consumption (P = VI) in a circuit would be reduced because of a smaller input current? Or is the power consumption calculated by the...

how is dsp different from devices which contain microprocessors?

For p-n junctions (connected as a junction rectifier), the forward-bias connection (battery's positive terminal connected at the p side) results in a narrowed depletion zone, because: the p side becomes more positive and the n side becomes more negative, thus decreasing the height of the...

Hello engineers, I learned the theory of transistors and that is all fine and dandy but in order to learn how to drive a car, you must drive a car, you cannot learn how to drive from books. So i googled some small transistor beginner projects and I stumbled onto a fun LED flasher...

Hello, I just bought lot of pnp and npn transistors. They are not labeled. How do i tell them apart?!

Hi All Given that one has a basic understanding of the working mechanism behind the diode, how can one develop a comparison between diodes, transistors and the valve. Best wishes, DaTario

Hi, I'm confused about something. Why is it that in magazines and videos it seems as though adding more transistors to a CPU will make it faster? Is it a numbers thing (like, instead of marking amps on signs, they show volts)? I mean, I understand that you can do multithreading, multiple...

I've read loads of explanations but can't find any that are detailed enough. Using a NPN bipolar transistor as an example: I know that the N type emitter and collector has a surplus of electrons and the P type base has a deficiency of electrons but I don't understand why current can't flow past...

Hi, I've looked everywhere for an explanation of this, including this forum, and none of them seem to satisfy the level of detail I am looking for. More specifically, I am interested in how processing units used a fixed setup of logic gates and transistors to perform universal computation...

I was just curious about trying to understand how transistors work, but didn't understand it properly. http://amasci.com/amateur/transis.html" I found this site through google, which claims that most traditional explanations have contradictions and wrong concepts. And that this simple...

Homework Statement 3. An emitter-follower is built using a transistor with β = 100 and R_E = 1000 Ω . (a) Whatʼs the input impedance with unloaded output? Now suppose the input is connected to a source having output impedance 500 Ω . Whatʼs the output impedance of the circuit? (c)...

"For low power transistors (under 1 W), the current gain is typically 100 to 300. High power transistors (over 1 W) usually have current gain of 20 to 100." — Electronic principles by Malvino I want to understand why the current gain is high for low power transistors and why it is low for...

i have no idea how transistors amplify ...how can the output gain be greater than the input gain ? ...efficiency is output/input which can never be greater than one, right?

Homework Statement The base-emitter voltage, V_be, typically never exceeds .6V. Because of this low value, the base-emitter junction must be protected against too high a reverse voltage. A diode is usually used to protect the junction as shown in the figure for a npn transistor. a. Explain...

hello good day, would someone kindly help me determine the part number of these 4 npn transistors here? pls help, cause my prof didn't discuss this yet.. and i don't have idea on how to calculate for the values of the transistor to determine tha part number suitable for the circuit... many...

[PLAIN]http://img685.imageshack.us/img685/2164/transistor.jpg having this transistor how can I find Vo? We know that βdc is too large and also R1 = 10KΩ and R2 = 30KΩ i just can't understand what to do, I mean it's pnp, so why does the current goe from top to bottom? shouldnt it go from...

Hi all, In following image thare are Positive(+) and Negative(-) signs on above and under VEB and VCB What's meaning of these signs?are they polarity of transistor? why beside connection to ground is a negative sign? thanks in advance.