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Questions tagged [amplifier]

An amplifier can be used to adapt the range of the signal to a requirement, to make it more robust for transmission, or to satisfy interface requirement (like input/output impedance)

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55 views

IR circuits: increasing sensitivity of simple analog receiver IR LED

I have the following circuit using a TSOP1738 and a simple IR receiver LED (analog): It's basically: a TSOP1738 put to my 5V uC pin, its OUT being read directly by the yellow channel of my ...
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1answer
65 views

Why is one of the transistors in ROM sense amplifier twice the width of the one opposite of him?

The picture is of Sense Amp design of ROM component in which a 'dummy' bit line is used to imitate the current so that the proper information can be derived from the memory cell by comparing the ...
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3answers
96 views

(Lack of) Miller Effect in Cascode considering Common Emitter and Common Base Seperately

I'm currently working on an analysis of a standard Cascode circuit, in particular why the frequency response is so good as it reduces the miller effect. I have had a very vague explanation given to ...
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2answers
42 views

Can I connect a 16 ohm output signal to a line input if I use a resistor in series?

newbie here. I have a Hi-Fi system and I wish to connect its output to a line input in another system while still being able to hear through the Hi-Fi´s original speakers. If I use the Headphone ...
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2answers
55 views

Power amplifier to drive pumps [closed]

I'm looking for a power amplifier that can drive water pumps (this system) at variable speeds in order to control water levels in tanks. This is for an engineering teaching lab. The amp should output ...
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1answer
69 views

Connecting bandpass filter to comparator generating excess noise

I have a band pass filter with a center frequency of 100kHz, a bandwidth of 10kHz, and a gain close to 1. Input signal is 100mV-150mV peak to peak with frequencies varying from 80kHz to 120kHz. I am ...
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26 views

Unwanted buzzing and reduced volume in a basic speaker set

I have the following device, which basically contains 18 songs. we can play the next song by switching the switch on and off. It also has a volume control. Recently it started to buzz a lot and the ...
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0answers
70 views

Non-Inverting Single Supply comparator hysteresis is too wide

I am trying to convert an input sine wave to a square wave. The sine wave is centered at 2.5V and has an amplitude of 200mV, with a frequency of 100kHz. I am looking for a hysteresis of 100mV ...
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1answer
65 views

Unity Gain Phase Splitter- Why outputs have different voltages

I’m trying to calculate the values of the biasing resistors for this phase splitter circuit. (I know the actual values of the resistors, but I just wanted to manually work it out). When I made the ...
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4answers
350 views

Gain in current but not in voltage -transistor “voltage follower” set up

Suppose we have the circuit set up as shown in the image. Also suppose that $$V_s=\overline{V_s}+v_S$$, where the smal v is for the variable component of the signal which varies much faster than the ...
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44 views

Issue with powering MP3 module with Amplifier

I'm not a electronics engineer/student, so please escuse me if my query sounds a bit naieve. I have a Mp3+FM module (link) which I can power with a regular micro USB charger(or desktop USB). As the ...
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73 views

How does this circuit with inverters work?

What this does this circuit do? I suspect it is an amplifier, but don't know how it amplifies. For example Inv 5 and Inv 6 are connected in parallel with reverse sides but there is a wire between ...
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1answer
52 views

Common Mode and differential Mode gain of this Cmos diff Amp inverter

This is one of questions our prof gave to students in recent years and im preparing myself for this exam. What is Common Mode and differential Mode gain of this Cmos diff Amp inverter? i understand ...
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4answers
99 views

What is a “phase reversal” choke and why is it used?

I was recently looking at the circuit for an HF radio amplifier called the "Packer" amplifier. It's a typical HF amplifier that puts out about 35 watts. The final output stage uses IRF510 MOSFETS ...
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2answers
78 views

High voltage gain block

Schematic 1 shows a discrete operational amplifier which is used as a gain block to make up to 450V out of 12V. Q3 and Q4 are used to generate a current which is used by the current mirror. This is ...
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2answers
80 views

Why are both bias resistors considered parallel in a common emitter amplifier?

When calculating the input impedance of a voltage divider biased BJT common emitter amplifier, we calculate the parallel resistance of the bias resistors and the emitter resistance. But why do we ...
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2answers
179 views

Can I convert a mini guitar-amp into a portable auxiliary speaker?

Being a guitar player, my brother got me one of those guitar shirts for Christmas that has a board with pressure sensors attached to it and an actual miniature amplifier. When the sensors on the board ...
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2answers
55 views

Building 3 Stage amplifier, Couple Questions

General question, how can I improve it? or make it more efficient? mabye there is something im missing... Questions: How can I deliver more dc voltage to the load? how do I improve my swing, im ...
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1answer
39 views

Phase shift near saturation mitigation in input stage amplifier — How does this work, why does this work?

I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer. Apologies for the quality... this is the best scan I could find. The design is furnished with the ...
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1answer
41 views

Typical Amplifier Output/Input Curve

I apologize for the extremely basic question, but I want to be sure. Ideally, an amplifier should have a linear output power to input power relationship. However, in most amplifiers (say a class AB ...
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1answer
43 views

DC Gain too low at higher voltages

I am having an issue with DC gain for a non-inverting op amp circuit. All I am trying to do is double the voltage from two DAC outputs (DAC range is 0 to 5V and I want it to be ~0V to 10V). The DAC ...
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2answers
54 views

Bipolar class-AB amplifier analysis questions

I am analyzing the following amplifier schematic Bipolar amplifier I'm wondering if their are any transistors that need to be cooled apart from the 4281A and 4302A output stage transistors? What is ...
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2answers
56 views

My transistor used in a transistor amplifier does not get turned off with PWM based input

I am working on a project; driving a DC MOTOR using an NMOS MOSFET amplifier and Arduino PWM signal. My problem is my transistor amplfiler is always on when I vary the PWM input value from 0 to 255. ...
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0answers
28 views

Measure the 'gain' of this circuit

I made this schematic using Ni multisim and I got asked to find the ‘gain of this circuit using a 1v p-p 1kHz sine signal’ and I was unsure about this because I’m not sure if it means voltage gain or ...
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1answer
316 views

Temperature coefficient MOSFET vs. temperature coefficient of BJT

If you use transistors for an amplifier scheme, you want to make sure that when you parallel devices, you don't start to conduct more current if your transistors heat up. I know that when using ...
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3answers
439 views

How to make repeatable Op-amp amplifier circuit

I did a simple op-amp based 100X gain single ended circuit. I tried to order 100 IC's and manufactured them. But found that out of 100 only 60 devices have same and expected baseline. What could be ...
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1answer
49 views

CT measuring circuit with PIC

I am using external CT to measure Current parameter. I am using PIC16F1938 to measure analog . Now here i am looking for circuit and calculation involved to get proper current rating datasheet Min ...
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2answers
456 views

LM386 motorboating that goes away with a resistor in parallel with the bypass capacitor on pin 7

I'm building a simple amplifier around a LM386. The circuit I'm using is this: The input is on pin 1 of the connector and is a square wave coming from a digital pin on a NodeMCU devboard. When I ...
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1answer
49 views

A wave generator of 64db max and an omnidirectional antenna of 3.2db what db can have max?

I have this wave amplifier of 64db max and an omnidirectional antenna of 3.2db and I have to transmit a sine wave of 82Mhz, are they suitable for me? What is the maximum gain I can get? I need at ...
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3answers
95 views

Vacuum tube stereo amplifiers with an odd number of tubes

While researching the world of vacuum tube audio amps, I noticed that many commercially available stereo amps have an odd number of tubes. Here's a random example. How can a decoupled stereo sound be ...
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1answer
71 views

Unstability with tda 2002 bridge configuration

I'm trying, for MONTHS (obviously not everyday, but I spent at least more than 80 hours on this) to do a 15 W audio amplifier with two TDA 2002's in a bridge configuration, following the circuit ...
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1answer
101 views

Amplifying heavily filtered attenuated stopband signal

The picture is of a noise analysis, but a signal that may be present in V1 would be filtered in the same way as the noise. At 100 KHz, the noise is attenuated by about 42 dB, from 568 uV to 4.7 uV. ...
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32 views

What is the Correct method to find the poles and zeros expressions?

What is the Correct method to find the poles and zeros expressions ? This is a replica circuit method used to calculate loop gain, please only consider the above part. I used pspice to find the bode ...
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2answers
92 views

How to simulate the exponential growth op-amp?

According to Wikipedia, the following is the exponential output operational amplifier. I would like to test this out in a simulated environment and see how this functions. For example give a sine ...
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1answer
68 views

Newbie question: Feasible way of amplifying 100+ channels of slow and low amplitude signal

I want to amplify signal coming in hundreds of channels (sensor array each producing a very low amplitude 30-200Hz signal). For every channel i care only about intensity of the signal (i don't need ...
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2answers
162 views

What's wrong with my1943/5200 Mosfet Amplifier? Blown on first run

I have just brought an 1943/5200 mosfet based amplifier board. Shopkeeper said it's rated for 24-0-24 AC. So I connected it with 24-0-24 transformer like this in image below. As soon as I turned the ...
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3answers
120 views

Why is the maximum efficiency of a push-pull amplifier 78.5%?

One of the practice questions for my upcoming test is this: After some googling, it seems like the correct answer is A. But why?
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1answer
31 views

Input Resistance and Mid-band Gain of a CE-CE Stage Cascade Amplifier

I am trying to calculate the Input Resistance and Mid-band Gain of a CE-CE stage. Here's what I got so far: I am having some doubts regarding my calculations though. Mainly with the input ...
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2answers
65 views

Why don't I get a signal on the load?

I don't get any signal on the load, what am I missing? Shouldn't it amplify the input signal? I have 50mA from the current mirror, the Vbe on Q10 and Q11 is around 0.75v
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1answer
73 views

Three stage amplifier [duplicate]

Well I need to design three stage amplifier Im stuck on the output stage, I need that the AC Current on the load will between 20mA to 100mA, but Top current I get is almost 5mA, cant over pass it ...
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2answers
86 views

Stk086 distance between pins? [closed]

I have been trying to make a footprint for this IC, and trying to figure out the distance between pins, it is a 10 pin ic what do you think the distance will be? What is the normal distance between ...
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0answers
50 views

Differential Amplifier Exam Problem

I am lost with how to approach part C and D of the question. In fact, I need some intuition with how to tune a differential amplifier.
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0answers
54 views

Portable Guitar Amp - Distortion, Volume & GND

I have tried following the given schematic There are 3 things I am unsure of (what I tried): The Volume 5k Potentiometer: I have tried adding a volume control to the schematic by placing the ...
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1answer
80 views

How to amplify current and buffer voltage

I have a battery supplying 5V@500mAh and an LED (the load) which draws 1000mA@5V (twice the current the battery supplies per hour). I found some circuits that have NPN transistors only and other ...
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2answers
53 views

Amplifier advice for speech sythesizer circuit

I'm designing a circuit that hooks up an SP0256A speech synthesizer to an AVR microcontroller and would like some help with the audio output amplification. The datasheet describes the output as being "...
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2answers
192 views

Audio amplifier for 600 ohm headphones

I am working on a design which must drive an audio output into 600 ohm headphones (aviation headsets). Normally, I would just use an off-the-shelf class D amplifier but I can only find ICs designed to ...
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1answer
47 views

MOSFET Differential Amplifier voltages via PSpice and by hand

I want to do an analysis on a differential pair and there is a problem when the pair is in common-mode, at least that's what PSpice says. I find that \$V_{DS}\$ of both MOSFETs is 1.1V and PSpice ...
4
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1answer
219 views

How do I appropriately power a headphone amplifier and where do I place the volume regulating potentiometers?

At the moment I am building a device that splits an analog stereo audio signal into 3 signals and amplifies 2 signals for headphones. I need to know how to supply -12VDC and where to put the volume ...
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1answer
53 views

2-stage BJT CC-EC amplifier [closed]

Using proteus I designed this amplifier: But I got this result: I don't know what is the problem in my design. I've been changing the values of the linking capacitors but didn't get any result.
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1answer
56 views

BJT LT spice DC transfer characteristic

Why is it that the DC transfer characteristic isn't flattening out at -5 v, so it looks like a Z-shape? I did a DC sweep from -10 V to +10 V. The input wave is a 2V sine wave for the graph below: