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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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152 views

How can I avoid saturation in current source amplifier?

I'm designing a class d amplifier with current feedback as in figure below with the following features: Vbus=50V Iout programmable from 100mA to 1A rms Vout=35Vrms max When the load overcomes the ...
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23 views

How to find the output voltage of a system with a computing amplifier?

I got a question regarding the following system. The only given value is the input voltage $$U_e = 8V.$$ Now the task is to find the output voltage $$U_a.$$ My question now is how do I find this ...
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2answers
60 views

LMV324 benefit of double feedback?

What is the benefit of the double feedback of the LMV324 op. Amp.? Why was that implemented in that way? From this scheme I have to understand why was implemented in that way
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2answers
2k views

Simple and powerful audio amplifier around BA4558?

I have two BA4558 ICs from an old home stereo. I tested them with simple negative feedback circuit for each channel and with power supply of +/- 6V. The speakers I used are most likely with 8 ohm ...
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1answer
62 views

LMV324 particular characteristic?

Our prof. at the university asked why the LMV324 is particular. Which is the characteristic that made this component so common in the modern electronics. He was talking about the ring gain or ...
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1answer
154 views

How exactly are the phase shift and cutoff frequency defined for a filter + amplifier circuit?

Say we had a voltage source connected to a Low Pass RC filter and that this filter was connected to the negative node of an Operational Amplifier, so we would have a filter followed by an inverting ...
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1answer
157 views

Building a VCCS with AD8220 Instrumentation Amplifier

This question is to help me with my work in building a VCCS for the excitation signal of an Electrical Impedance Tomography measurement set-up to use with EIDORS. I have only basic knowledge in ...
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3answers
79 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
417 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
159 views

PCM1789 DAC direct connection to TPA6138A2 headphone amplifier?

Is it possible to directly connect PCM1789 DAC to TPA6138A2 headphone amplifier? According to datasheet PCM1789 output are differential outputs and the input of TPA6138A2 is also differential inputs. ...
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1answer
26 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
46 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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2answers
416 views

MOSFET Amplifier: Maximum Signal Swing without Clipping

I have a degenerated common source amplifier. I want to know what's the maximum input signal I can apply before the output signal begins to clip. What I currently do is to increase the input signal ...
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2answers
40 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
54 views

Power amplifier to drive pumps [on hold]

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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2answers
192 views

Guitar Amplifier Peavey Backstage Plus

The fuse of this guitar amplifier blows. Changing the output transistors had the amp working for a while, but then after a while the fuse blew again. The output transistors that were changed are new....
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1answer
162 views

How to find collector resistor value in bjt differential amplifier

What value R2 may have in that schema? Anyway it will be loaded by pn-junction of Q5 and will have fixed voltage drop near 0.65V. What value R2 must have if the current source is used instead R1? The ...
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1answer
49 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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1answer
172 views

How can I correct instability in a push-pull transistor amplifier?

In our EE lab, we had to build the following amplifier. It is from this lab manual, page 40. A week ago, I built it successfully, with 2n3904/3906 and d44vh10/ d45vh10 for the power amplifiers (Q3,...
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1answer
84 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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0answers
45 views

Common Emitter Amplifier wrong chart

I'm going to be honest with you guys. I'm totally green when it comes to electronic, but I need to pass labs (as you do). I was given scheme of what I think (I did some digging) of is Common Emitter ...
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2answers
158 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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0answers
23 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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1answer
136 views

Identifying OEM amp Connectors

Can anyone help identify connector type for A & C below or suggest site/keywords I could use to narrow search? I have sent inquiry to several sites selling automotive connectors and Googled ...
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0answers
44 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
41 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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53 views

Amplifier for 22Hz transmitter [closed]

Can anyone help me find an amplifier that can amplify 22Hz signal which is to be transmitted to a distance of 25m through a copper wounded antenna...I have tried with a voltage (sine wave) of 9V ...
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0answers
74 views

Amplifier for very low frequency sine wave [closed]

I use arbitrary waveform generator TGA12104 for generating sine wave with following parameters(voltage - up to 10 V, current - up to 0.2 A, frequency - up to 0.1 Hz (most often about 0.005-0.05 Hz). ...
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4answers
346 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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1answer
216 views

Question about common mode feedback

Hi, in the image below (taken from Design of CMOS Analog Design Circuits by Razavi), a high gain amplifier is used to provide common mode sense and feeback by controlling the current through M3 and M4....
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0answers
37 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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4answers
92 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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67 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
37 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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0answers
31 views

Best 2n2222a based audio amp schematic for piezo buzzer disk contact microphone for human speech? [on hold]

Could anyone point me to a good, or even awesome circuit schematic using the 2n2222a transistor in an audio amp for a piezo buzzer disk contact microphone? I intend to use it to capture and listen to ...
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2answers
75 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
74 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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3answers
954 views

Piggy-backing off power amplifier outputs

My motor-scooter has a built in radio, with a small speak either side of the front panel, below the handlebars. It's a JonWay, i.e. cheap Chinese, so I suspect the radio is more suited to developing ...
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2answers
52 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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2answers
448 views

Amp troubles - noisy TEA2025

Recently I got my hands on a small amplifier board containing two TEA2025 ICs. Not sure what had it been used in previously, but the sound was acceptable, at least when removing some resistors that ...
3
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1answer
36 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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4answers
214 views

Filter-Amplifier circuit for Low Voltage I/P circuitry

I'm designing my first ever circuit for a hobby project. I've a sensor that outputs in mV (1 to 2) and a controller with ADC. The ADC is 16 bits, VDDA = 3.0 V, Temp = 25 °C, fADCK = 1.0 MHz. Since the ...
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0answers
21 views

Fiterless Class D amplifier: the PWM and Switching stage

What is the minimum voltage and current to drive a MOSFET switching stage for a filterless class D amplifier having 86% efficiency? What ae the calculations needed to find this out?
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1answer
1k views

r(e) Model of a Transistor

While studying the re model of a common emitter transistor i found these two different models that are considered equivalent. But i do not understand how they can be equivalent when in one figure ...
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1answer
37 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
261 views

QUCS simulation radio transistor amplifier

I'm trying to design a small amplifier for AM signals to use before the usual diode-C-R detection (the reception in my area is very poor). I devised a QUCS simulation as below: The diode and ...
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2answers
52 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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1answer
186 views

Understanding Amplifier Function

I am looking at a schematic of an amplifier system featuring what I think is some kind of feedback / damping loop on the speakers woofer. I've attached the schematic showing the "damping resistor". I ...
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1answer
40 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
453 views

Excessive noise in amplifier circuit when switching from DC power supply to AC-DC adapter

I'm working on breadboarding this amplifier circuit before transferring to a perf board. When we power it from an adjustable DC power supply set to 12V, the audio output sounds clear. When we switch ...