Questions tagged [emitter]

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2answers
46 views

LTSpice RF transistor 2 emitter “the instance has fewer connection terminals than the definition”

I am trying to use the Infineon spice model for BFP640ESD (link for library file), but it has two emitter terminals and I'm not sure how to use it since the BJT models have only 3 terminals and I need ...
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1answer
56 views

Emitter-Follower Class A amplifier

I was trying to solve a problem from SEDRA-SMITH book. I got stuck so I refer to the solution. When Studying how the author solved the problem I got even more confused. Let's refer first to the ...
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0answers
35 views

Maximising output amplitude

How can I modify this emitter follower circuit to get maximum amplitude output with no distortion? Re = 2.25k ohms, Rb1 = 57.3k ohms, Rb2 = 96.1 I currently have 0.96 gain Vcc is limited to 9V and ...
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1answer
51 views

Definition and calculation of distortion in grounded emitter amplifier

My question is related to How can I set the quiescent current for a grounded-emitter amplifier and AoE3: Grounded Emitter Amplifier Distortion originated in TAOE3 on the nonlinearity of grounded ...
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0answers
208 views

Is there a faster alternative to the HT12E / HT12D IC?

I am looking for a quicker alternative to the HT12E encoder IC. This IC lets you encode 8 bits of adresse and 4 bits of data. Once the bits are encoded, it outputs a frame containing all those bits ...
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4answers
254 views

Voltage divider bjt biasing with thevenin theorem

Say I have this circuit: I am confused as to how using Thevenin's theorem yields correct results. Say I choose a bias point on an I-V characteristic curve at the IC = 16mA. If this transistor has a ...
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1answer
109 views

CE power amplifier design

I am trying to further my knowledge in discrete transistor design so I am designing a CE power amplifier to drive a speaker. What I have trouble with is determining where to bias my BJT at. I can't ...
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1answer
128 views

Is this resistor routed correctly?

For a friend I'm trying to make a fuzz pedal and found this very flexible fuzz circuit, called "The Fuzz of 1000 Faces," at instructables, credits to Randofo. However, since it's an old post, I ask ...
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1answer
164 views

Design an emitter follower to operate in the audio range (20 Hz - 20 kHz)

I am now self-learning with the "Art of Electronics" book by Holowitz and Hill, and I encountered a problem understanding one example from the book. Here it is: And here is the explanation for the ...
1
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1answer
123 views

Emitter follower for parallel LED switch

I’m trying to confirm that the solution posted in https://electronics.stackexchange.com/a/60868 will work for my application. I have four yellow LEDs with a 2v drop (yellow) and 30mA max current I’...
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2answers
55 views

How measure the opening angle (integral rotation of a cone) in a emitter

I have an IR emitter (EMIRS200_AT01T_BR080_Series) with the datasheet showing the Optical output power versus the opening angle as below. Now, I would like to understand how interpretation the ...
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2answers
70 views

Understanding Responsivity of an IR sensor paired with a black body IR emitter

I'm building an air quality measurement system with the following components: IR Dual Channel sensor by Pyreos Axetris IR Balck Body emitter Reading the sensor datasheet I've seen there's the ...
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2answers
100 views

How does a Black Body IR Emitter work?

I'm going to buy some IR sensors for gas detection measure. As soon as I need lights on specific waves length for measure specific gas, I have opted for a black body IR emitter, specifically this one ...
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0answers
111 views

Why is a voltage across emitter and base required in a bipolar transistor?

I read the reply to this question but I cannot really make sense of it: In an NPN transistor, why doesn't current flow without applying a base voltage? if I have a npn-transistor and and apply a ...
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0answers
134 views

Why do I have voltage on Collector and Emitter when NPN transistor turns on? How to get rid of it?

I have a 2N3904 NPN transistor. I'm feeding the base 5V. the transistor turns on just fine and it shorts the collector and emitter. However, when I turn my meter on volts, I read around 1- 1.5 volts ...
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0answers
117 views

CE/CB BJT Amplifier(s) + Load Lines!

This diagram from a lab assignment is not making sense to me...any help would be greatly appreciated. I don't understand what \$I_{C_\max}\cdot R_e\$ is and why it appears on this diagram. Even if it ...
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3answers
116 views

Infrared High Intensity LED with two anodes?

I got an infrared led emitter, with model ""L1I0-0850060000000" and the datasheet is plenty of technical data but I can`t find why it has three terminals - 2 anodes and 1 catode. Usually it's used for ...
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0answers
148 views

Drive 433Mhz emitter and Attiny with two coin cells

I would like to detect when the postman put mail in my box, so I was thinking about a simple attiny with tilt sensor (which would wake up the attiny) and a 433 MHz emitter: The problem is that one ...
1
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1answer
85 views

40 kHz Emitter Frequency Response

I've recently purchased 40 kHz transceivers and I tested its frequency response in anechoic chamber using a B&K microphone located 90cm away from the emitter. The response provided in the ...
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2answers
307 views

Does Differential Amplifier Emitter behave as ground in AC-analysis?

I am trying to solve various differential-amplifier homework problems for which I have the solution to study. For the simplicity of most problems we are able to neglect base-currents. Moreover, it ...
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3answers
682 views

Are IR emitter frequencies adjustable? Can modulation of the emitter variate material absorption properties?

A common LED emitter, Gallium Arsenide, apparently has a wavelength of about 760 nm. Then on the receiving end, there is a filtering circuit to eliminate ambient IR and to demodulate the message. Can ...
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2answers
2k views

What are the Advantage and uses of voltage follower circuit over emitter follower

Can I use voltage follower and emitter follower for same purpose
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3answers
261 views

AC Analysis of emitter circuit, why can I ignore resistance R1 but not Rc?

I am trying to calculate the small signal voltage gain of this circuit but I am having a problem comprehending the last step. I rewrote the circuit like this But the solution says this: Which would ...
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1answer
2k views

How to calculate the collector resistor of this emitter circuit?

My supply voltage is +10 V, collector current at my bias point is 5 mA, base current is 28.8 uA, amplification is 173.3 I already calculated the base resistor to \$R_1=\frac{V_{CC}-V_{BE}}{I_b}\$ and ...
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2answers
353 views

Collector must be more positive than the emitter

My book (The Art of Electronics by Paul Horowitz and Winfield Hill) is stating something that seems to be the opposite of the example it is using. I am not going to school for my studies so I ...
4
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1answer
1k views

Are there any SOT-23 BJT's with swapped Base and Emitter pins? [closed]

The standard NPN BJT in SOT-23 package has the following arrangement of pins: Do you know of any transistor that has pins 1 and 2 reversed? So that 2 is the base while 1 is the emitter (Doesn't ...
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5answers
5k views

Finding the Base-Emitter Voltage in an NPN Transistor

The problem asks to find the the real value of base-emitter voltage, \$V_{BE}\$ and the corresponding \$I_C\$, and \$V_{OUT}\$ in the figure below: \$V_{CE(sat)}\$ is given but the transistor is not ...
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1answer
67 views

Are there methods to stabilizing \$V_{BE}\$ [closed]

For \$V_{IN}\$ >> \$V_{BE}\$ (\$V_{IN}\$ in reference to GND), the \$V_{BE}\$ is quite stable typically only varying in 8mV for silicon NPNs and gets smaller when the emitter is conducting less ...
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4answers
872 views

Finding the Real \$V_{BE}\$

In a BJT in common emitter configuration, what formula can you use to calculate the real \$V_{BE}\$ so that you don't have to approximate it as \$0.7V\$? The problem below asks for the actual value of ...
1
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1answer
260 views

NPN transistor energy drain from base to emitter?

I have the following example circuit: I do not understand why this lights the LED. For my main project I am building a circuit that has a button connected to an output as well as the collector of the ...
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1answer
4k views

What are the reasons that the emitter is heavily doped in an NPN BJT? [duplicate]

Is doping the emitter more than the collector crucial? Would current not flow at all if both regions were equally doped? Why? Is there a way to explain this in a simple fashion?
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3answers
313 views

Why are these resistors considered in parallel in the DC equivalent (Com Emitter Amp)

So here is a page from my text book, the Common Emitter Circuit is on the top and on the bottom right you can see the DC equivalent circuit , my question is that by looking at that dc circuit i do not ...
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3answers
857 views

Finding the operating point of a transistor circuit

I want to find the operating point of this circuit: where we have a npn-Transistor and \$R_V = 47k\Omega\$, \$R_C = 1k\Omega\$, \$R_E = 4,7k\Omega\$, \$\beta = 100 \$, \$+U_B = 10V\$ and \$-U_B = -...
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1answer
365 views

IR emitter LED with jack 3.5

Currently I'm using an IR LED connected directly to a PCB where an Arduino UNO is connected. When I send a command with the Arduino, the LED sends what I want to an IR receiver. Now I'm thinking to ...
0
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1answer
87 views

Calculate the parallel value of resistors at base of common emitter amplifier

I don't know if questions can be asked like this here but if they can I want this question. In an exam paper I saw a question to determine the parallel value of the R1 and R2 resistors in the image ...
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1answer
294 views

Pspice Common Emitter Schematic Missing Values

I am doing some homework for universiy and PSpice keeps saying that there is some missing values.I cant seem to find a solution in my books so I though that i might share my issue with you and ...
1
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4answers
3k views

A question on voltage divider resistances used in BJT biasing

I'm reading a text on BJT common collector amplifier biasing. Text says: The voltage divider (R1 and R2) is used to give the input signal (after passing through the capacitor) a positive dc level ...
3
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3answers
1k views

Confusion on the meaning of a BJT emitter follower's output impedance

Above figure is a BJT transistor emitter follower. I can understand that in an emitter follower when talking about its input impedance what meant is Vb/Ib and here it is equal to (hfe+1)*R. The idea ...