Bjt Definition and 216 Threads

Homework Statement You want to use a PIC microcontroller to drive a motor in a clockwise direction at either 0% speed (when the PIC output is 0V) or full speed (when the PIC output is +5V). This motor draws 500mA at +5V while the output of the used PIC is limited to +5V and 20mA. To solve...

Does anyone know how to build a simple BJT Differential Amplifier circuit? And also need to gain around 20..emergency please help. Thanks for that. As I build a circuit but is not simple enough, please have a look for that and any comment for this circuit?

Hey guys, I am working on my lab with BJT with a Common Emitter Configuration. One of the steps asks me to measure the DC Operating Point, however I am not sure what they want. What I think they want is for us to find the point VCE where the slope of the collector current vs VCE intersects...

1. As compared to the circuit as shown in the figure, i applied KCL in the circuit and still couldn't get the right Ic current at the collector as shown in the simulation. 2. The IC current for XMM2 is 1.64mA but i got 22.12mA instead in my calculation. (I'm using the Ic=βIb where...

Homework Statement See first figure attached. Homework Equations The Attempt at a Solution See 2nd figure attached for my work so far at attempting the design. The last figure is what my textbook gives as the small signal analysis of a BJT differential amplifier with emitter...

Homework Statement I am trying to find the KVL equation for this BJT in order to find Ib. http://www.ece.auckland.ac.nz/oasis/a/att/qtatt/2028/2/261/IM010 Homework Equations The Attempt at a Solution My current equation looks like this. Vcc - IcRc - IbRb - Vbe = 0 I am...

does bjt amplify dc signal? why or why not?

What is the BJT base current if the base is connected to a zener diode like in the circuit here - http://www.satcure-focus.com/tutor/page5.htm With a voltage divider it's thevenin's equivalent. But with zener, should I consider it as a voltage source?

Is there a way to minimize the temperature dependence of VBE. I am trying to design a BJT switch, that will turn on at a particular voltage(43v). ckt attached. The base sees 0.65v when Vcc is 43v or more (resistor divider bias). This turns on the BJT. It should be off when Vcc is 42V or...

Hello, I have a quick question about Characteristic curves. [PLAIN]http://pokit.org/get/1958a855486487230cd4e3c0a1cc0908.jpg First: Do these curves go to infinity, i mean in theory? If I had a steeper load line, I would hit saturation later. And what about that portion of load line between...

Hello, I am trying to figure out at some level(not fully) Hybrid PI model BJT. Only one thing bothers me. Does it matter if the v0 is + or -. Is for npn transistor v0 -ive and for pnp +ive? How do I figure that out and does it really matter, and if not why?

Homework Statement [PLAIN]http://dl.dropbox.com/u/14490370/bjt.png Homework Equations beta=Ic/Ib By 'ON' I think the lecturer means the saturation region and by 'OFF' he means cut off. The Attempt at a Solution a. My reasoning is Ib= (Vs-Vbase...

hi all i have some questions about a commen emmiter bjt amplifier circuit . if i had this circuit : and i want to find the ripple of voltage in outout : i will use this equation : V_{O(p-p)}=2I_{CQ} (R_L || R_C) but why i put R_L || R_C not R_L || R_C + R_E or how i conclude that...

Hi I'm having some problems with using the graphical method to determine the output characteristics, the question and the answer are all included in the document attached. I understand the process of putting the load line on the graph but for this application i have no idea what to do. Many...

I am just wondering, how do we add an ideal BJT npn transistor to an LT Spice circuit? From the component button i have added an 'npn1' will the default values be ideal? And what if you want to change the beta for the transistor how do you do this. I found a file called standard bjt, it...

When the NPN is in the forward active mode The base emitter junction is forward biased and the base collector junction is reverse biased. But isn't it possible for the base collector junction to break down? Or do we assume it never breaks down? Also does anyone know any good water analogies...

Homework Statement given input as 100mV peak and expected output to be 10Vpeakto peak...i am having trouble on how to find the different values , like resistors , capacitors ...i am planning to use fixed bias circuit (common emitter configuration) and my transistor gives a value of hfe=...

When using BJT as a pass element in series pass regulation, why is the NPN drop more than the PNP. Both have BE diodes. Why is the drop (VCEsat+VBE) in case of NPN and drop is equal to VCE sat in case of PNP. Can someone also explain VCE sat using diode equivalent of BJTs.

I can't understand an opamp circuit whenever there is an active element in the feedback loop. For example, in the current monitor ckt(attached). I don't understand how it works. I can't figure out how the opamp offset and BJT gain would affect the output. This ckt is from national semi AN31.

Who can explain what happens (in terms of electrons) what happens when base current is zero, especially why current flowing to collector is zero under this condition?

I don't understand the Vce voltage drop of a BJT. If I try to think of the BJT as 2 diodes - Base emitter diode and base collector diode. Vce is the voltage across the cathode of the base-collector diode and cathode of Base-emitter diode. How can it be 0.2V(when the BJT is saturated). I don't...

I've created a multistage amplifier in LTSpice IV and want to use actual measured hfe (Beta) values for each of the transistors, though I can't find an easy way to modify them. I could modify their library values in notepad, but I am using the same transistor model for a few of the stages and...

(This is not homework) Okay I'm writing a lab report and just writing some discussion. Also I am curious myself. I'm a junior in computer engineering. I want to discuss the differences between BJT and MOSFETs as amplifiers and anything like pros/cons for each. Also why is the BJT...

Hello, I had a basic analog electronics course this summer. Now that I'm trying to design my own circuit with a bipolar junction transistor (both for fun and to prepare for the future), I'm finding I don't really understand how and why I have to follow certain procedures to get maximum output...

Hi guys, I'm really confused as to what "Base-Emitter Voltage" is. I thought it was the voltage difference between the base and the emitter, but apparently it's no such thing? If you could explain it, that would be fantastic. The reason why I ask is I'm not sure if I'm going to blow up...

Hey folks, First time poster. I'll try to be as specific as possible. We have been working on our senior design project for one semester and we have a semester remaining. We came to a snag after being very successful with our design. Essentially, we're using an arduino deumilanove micro...

Homework Statement Find IB, IC, IE, VB and VC in Figure 7, where Bdc is 40.The Attempt at a Solution VCC-ICRC-VCE=0 IC=BdcIB VBB-IBRB-VBE=0 IE=IB+IC VBE=VB VCE=VC

I'm utterly confused about this concept and the textbook quite efficiently confuses me further. I'll just try to explain it with an example: The circuit has a V(cc) = 10 V and V(ee) = -10 V. V(c) = 2 V, V(e) = -1.7 V, V(b) = -1 V, I(c) = 1 mA, I(e) = 1 mA. It says that allowable signal...

Homework Statement The questions states to draw the output voltage (Vo) for two full cycles knowing that we have a sine source with 2v amplitude.Homework Equations The Attempt at a Solution I've found: Ic = 1.303 mA Av (gain) = 1I can't figure out why the output signal gets clipped while on...

Hello, I have taken some measurments following a proposed experiment in a begginners electronics book to calculate the beta-value of an NPN BJT transistor. The circuit was as follows: ____________ | | | | | | + R_B R_C 9V | C_| - B |...

Hi, In a common emitter amplifier circuit, I am considering the base-emitter junction. When you apply a base current, you get the base-emitter resistance, according to thermal_voltage/base_current. But when you get that resistance and place it in it's position in series with the emitter...

how to understand each sub grap all those lines inside http://i46.tinypic.com/124j3hd.jpg

hello friends... how to solVe this question...i have found its answer is D OPTION. :smile:

I was reading about IGBTs. They can handle much more power than Mosfets and BJTs. I thought Mosfet could handle more power than BJTs, since RDSon was munch lower than BJTs. Can someone explain why?

I just want detail information about BJT circuits

Homework Statement Determine the mode of operation of this npn BJT, given the terminal voltages. E = -0.10 V B = 5.0 V C = 5.0 V Homework Equations Below The Attempt at a Solution According to the general rules, the EBJ is forward biased and the CBJ is reverse biased, leading to the...

Can someone clarify the overall purpose and implications of biasing a BJT Class A amplifier? I just can't get my head wrapped around the entire purpose. As far as I know, biasing the circuit will place it in a certain operating region, but I don't know the limits/implications of doing this...

Hi, as mentioned in my previous thread, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital (software) version. I know 'nothing' about EE, I'm a Computer Science guy, so hopefully this question is not too easy :-) This...

Homework Statement I have to design a multistage bjt pre amplifier with following conditions gain 20-60dB input impedence >= 5K ohm output impedence <= 100 ohm bandwidth 300Hz - 3MHz source impedence 600 ohm load impedence 10 K ohm can someone please give me a good tutorial link...

hello everyone ...I'm new here and I have so many questions need to be answered ! so I will be really really really thankful if you help :) what should be the out put voltage waveform shape on the Oscilloscope "Vce" , when the 1Kohm resistor inserted and when it's not ... the BJT as...

Homework Statement Consider the following circuit http://img109.imageshack.us/img109/80/circuit1.jpg IL, current through R3 (unknown resistance must be found) Homework Equations Vth=(Vcc/Rtotal)*R1 (V tThevenin) Rth=R1//R2 (R Thevenin) Vbe= 0.7 volts (silicon diode) Beta...

In a BJT Differential amplifier, how to find the maximum and minimum values of the common-mode input voltage? Beta and the resistors are given.

I'm confused about how exactly the output resistance and other resistances are set up in the small signal model. Is this small signal model correct? Please regard underscores as a subscript. Is r_0 always connected between collector and emitter?

Iam sorry if it is a very basic question but iam unable to understand this if u take a common emitter configuration of npn transistor the emitter is common to both the input and output terminals and to operate in the active region 1. the emitter to base should be forward biased i.e n and p...

A bit awkward question but still it confuses me... A BJT is a current controlled device because its output characteristics are determined by the input current. A FET is voltage controlled device because its output characteristics are determined by the Field which depends on Voltage applied...

Hi to you all, I'm reading about semiconductor devices on Muller-Kamins' "Device Electronics for Integrated Circuits" and I have some problem understanding the base transit time of a bipolar transistor. I read that when the npn bjt is forward biased the emitter injects electron in the base. In...

static current gain of BJT? to increase the static current gain of a BJT what should i do ?//////// 1.base is made thin and heavily doped 2. collector is made thick and heavily doped 3.base is made thin and lightly doped 4.emitter is made thin and heavily doped its an MCq...

Homework Statement 1. Vcc = 15V 2. 10 Vp-p symmetrical output swing 3. Av >= 1000V/V 4. Rin >=10k 5. Rout <=500 6. flow <= 100Hz 7. fhigh >=1MHz 8. Power Consumption <= 500mW 9. Rload=2k Homework Equations Many :) The Attempt at a Solution We...

Hey everyone, Im currently reading Horowitz & Hill and am a little confused on the topic of the intrinsic emitter resistance (re). I understand that this resistance is essentially the dynamic resistance of the base-emitter diode. I assumed that when analyzing a circuit this resistance...

Hi guys..how do u generate two identical voltage signals using the simplest BJT circuit?appreciate any help...