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)

2
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1answer
55 views

How to amplify a signal for piezo transducer from 1 Vpp to 200 Vpp at 400 kHz and 500 pF load

I'm a researcher working with phased ultrasonic transducer arrays. I need to amplify a sine wave at 400 kHz and 1 Vpp to 200 Vpp. It has a capacitive load of 500 pF. I'm little ...
1
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1answer
27 views

Capacitance to useful signal conversion

Working on a project, where we need to measure the change in capacitance(capacitance change roughly from 0.5 pF at the start, to 20 pF at the end of the measurement). On the variable cap, only the ...
3
votes
2answers
112 views

Confusion between the necessity of maximum voltage and maximum power transfer

This is a conceptual question therefore I want to ask with an example. I'm wondering in which cases impedance matching is used. For example, if one has a sensor which can be modeled as voltage ...
1
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0answers
34 views

Audio Amplifier Power Usage

I'm looking to add an audio amplifier to a circuit, in this case the TPA0211 in 5V mode for a full 2W of output. My rather dumb question is this: I should expect at least 400mA of current draw from ...
2
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1answer
53 views

Improving Power Amplifier - Digital Bias current set

In the following power amplifier: the MOS bias current is set by VR2. T4 acts as a temperature balance. The ensemble R15, RV2, D5, T4, T5, R14 act as a current source. VR1 act as offset adjustment....
0
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1answer
41 views

Equivalent power BJT transistor 2sa758 and 2sc898 for Sansui au 6600 Amplifier

I am restoring my Sansui au6600, at the moment I am recapping it, however I will have to replace the two final power transistors for the left channel which I found out to be faulty. The parts listed ...
0
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1answer
51 views

Compensated vs uncompensated Op Amps [closed]

What are the advantages/disadvantages of compensated and uncompensated op amps? Thank you in advance.
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3answers
81 views

Difference between two integrator circuits

What is the difference between the two integrator circuits? They are used in an amplifier with feedback. There's heaps of information online about the one on the right but not so much about the one on ...
0
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1answer
120 views

Common Emitter Amplifier design problem - seeking quick solutions updated

Looking for a quick check of solutions to the below problem. Design requirements: AC gain of G = -10 Output impedance of R = 4.7 kΩ T1 is 2N3904 npn transistor with β = 100 and base-emitter voltage ...
1
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1answer
53 views

The proper way of using gm/Id plot for designing an amplifier or OTA

For any design of an amplifier or OTA, we are given the specs which we need to achieve including: Gain UGBW or 3db BW Slew rate Power consumption Phase Margin Load capacitance I would like to ...
0
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1answer
60 views

Large ac input class AB biasing

I'm trying to bias the following circuit to power an 8 ohm speaker with an 8Vptp output. The following are the calculations I've done to get this current setup but the output is only good up to 1Vptp ...
3
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2answers
159 views

Gain of Non-Inverting Amplifier Does Not vary with Resistor Values

I am trying to build a non-inverting amplifier using a LM7171 op amp, and I am implementing it with potentiometers as Rf and R2 so that I can smoothly control the gain of the amplifier (and easily ...
0
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1answer
98 views

Common emitter amplifier with load resistance

I can't seem to grasp how to calculate the values for a common emitter with a load resistance, to cascade an amplifier in multiple stages. I'm trying to obtain an 8.5-9Vptp output from a 12V supply ...
0
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1answer
57 views

Need help understanding how this decoder IC & differential amplifier circuit works

I need help to better understand differential amplifiers, when interfaced with an decoder IC. For the circuit below, which is from the reference design here: It shows a mono differential amplifier (...
0
votes
2answers
56 views

Confused on voltage potential

I’ve been doing much research the last couple of days about electricity. I have a pretty good understanding of Watts, Joules, Coulombs, Amperes, Ohms, and I know Ohms law finding voltage and all and I ...
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1answer
70 views

Cascading Op Amps for Phototransistor Output Conditioning

I am working on a project in which I am using an IR phototransistor to detect changing low levels of light. Currently with very high load resistance I can get a reading of 40-60 mV but I would like to ...
4
votes
2answers
1k views

Single supply non-inverting amplifier using op amp

I'm working on building a distortion guitar effect pedal for an analog electronics class I'm taking. I am struggling with building an amplifying circuit using an op amp (we just began learning about ...
0
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1answer
40 views

How to find the Common Mode Rejection Ratio of this circuit?

My attempt was like, by using the formula, I can get, \$CMMR=\frac{\sqrt{2\cdot4\cdot8\cdot5\cdot10^{-6}}\cdot44000\cdot2}{x}\$ For the denominator, I used both 10% and 20%, but all the finals were ...
-1
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1answer
50 views

BJT Cascade Difference Amplifier Exercise

I need help with the exercise. The questions: Add or Design Components to have a current source I=2 mA at the picture. Draw equivalent small signal,low frequency model. Find Ai, Zo, Zi. If ...
0
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2answers
60 views

How can I get a loud noise out of a 15mm piezo disc?

I need to get an as loud as possible noise out of a 15mm piezo disc, using only the 3V from Arduino. I know I will have to make some sort of amplifier circuit, and I have attempted to make a basic ...
1
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1answer
82 views

2N2222 transistor datasheet saturation current

I am designing a 2N2222 transistor common emitter voltage-divider amplifier. Using 9V for the power supply and trying to make the loadline to determine Q. How do I determine the sauration point ...
1
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1answer
62 views

Input impedance of differential amplifier

Can someone please explain to me, how I should look at the input impedance of the opamps, seen through the voltage \$V_1 V_2\$? I have two questions on the differential amplifier: Why doesn't the ...
0
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1answer
33 views

Harmonic detection using lock-in amplifier

Can a third harmonic of a signal be detected using a lock-in amplifier under the same parameters fixed for collecting the fundamental or the parameters needs to be adjusted.Here by parameters I mean ...
9
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2answers
2k views

What property of a BJT transistor makes it an amplifier?

I know how we can amplify a given signal using BJT transistors by biasing them. But I would like to know what is that crux property which enables BJT transistor to act like an amplifier. Is it the ...
1
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0answers
100 views

LM358 Headphone Amplifier Oscillations

I'm trying to build a very simple headphone amplifier for my bass guitar. The bass has a built-in amplifier, meaning that unity-gain is sufficient for my amplifier, I essentially only need a voltage ...
0
votes
2answers
96 views

Calculating base-emitter current of a BJT, with emitter connected to ground (no resistor)

Much like the circuit above, most BJT amplifiers use an emitter degeneration resistor to stabilise the bias. It's relatively straightforward to calculate the base and collector quiescent currents. I ...
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0answers
24 views

is the gain for this differential bjt pair correct?

I'm referring to the diff pair consisting of Q1 and Q2, ignoring the rest of the circuit for now. I've attached a pic of my diff pair small signal model and what I calculated for the small signal gain....
-1
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1answer
52 views

Supplying two IC within a circuit with different voltage range (1.8v to 3.6v) and ( 4v to 5v) with battery power [closed]

We are designing a circuit that has two ICs with different supply range. it will use micro batteries as supply unit. What is the efficient way to feed two ICs together and waste minimum energy. Of ...
0
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0answers
33 views

Gain and output impedance in a differential amplifier

When looking at a differential amplifier: Why does gain increase when the output impedance is increased? For example, replacing a differential amplifier biased with resistors for an active load (...
0
votes
1answer
99 views

Identify of Amplifier class?

I want to build an amplifier. I got a circuit diagram from a website, Amplificador Monofónico de 250 Vatios Cuasicomplementario. I want to know the class of this amplifier.
2
votes
3answers
137 views

Potentiostat Drift

Firstly - First post so let me know if I have done anything wrong. Okay, so I am tying to get this biased potentiostat to work. I have attached the circuit below. I am using the following sensor: ...
0
votes
1answer
55 views

Noise when amplifier and chromecast share a power supply

simulate this circuit – Schematic created using CircuitLab I want to power a chromecast and an amplifier from the same power supply. When the dc/dc converter is powered by a separate power ...
0
votes
1answer
60 views

What's the actual difference between voltage gain, current gain and power gain?

Why do we intend to obtain different gains at different places? In an emitter follower for example, There's no voltage gain, but there's current gain and therefore it has power gain. Okay, how's ...
1
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1answer
61 views

Multiple feedback single supply

I've been trying to get a multiple feedback lowpass filter to work. With this schematic. The filter works in the simulation but when i try to build it, it gives no output. The op amp used to build ...
3
votes
4answers
130 views

analysis of two stage preampplifier

I found this circuit in an old book. It is a two stage audio amplifier I wanted to try it but I didn't know how to do the dc analysis. I couldn't find any current. Could you help me to find a ...
2
votes
2answers
257 views

Voltage output waveform of a differentiating amplifier

I have the following picture of the input and output voltage waveforms from a differentiating amplifier as shown below: And the schematic is as shown below: My teacher claimed that these waveforms ...
1
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1answer
33 views

Calculation of DC power drawn by circuit in Class A power amplifier

simulate this circuit – Schematic created using CircuitLab I'm watching Prof. D.C. Dube's lecture (timestamp included) on power amplifiers, and I'm confused about the calculation of DC power \$...
0
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1answer
37 views

Power Contours for a Power Amplifier

I am having a bit of difficulty generating the power contours at a Pin where Pout is 17dBm. I am doing a PSS analysis in Cadence Virtuoso. I am sweeping the phase along with a parametric sweep of the ...
2
votes
4answers
148 views

Can anyone identify the components circled in black? Weber 6049A Schematic

I have a 1936 era Weber amplifier (6049A.) Can anyone help me identify the 2 components I have circled in black? Red/Purple and Orange/Black (one of the other components also has a green circle on ...
1
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1answer
70 views

Amplifying Sinusoid From Microcontroller to ~40V 3-5A

I’m investigating transient switch arcing that occurs in a 3 phase switching unit. I am planning on generating the phase signals with an STM32F4 using DAC and DMA with timing separation for the phase ...
0
votes
1answer
47 views

Volume Control for Mixer Circuit using DAC Refence

I am mixing two stereo audio signals together and would like to control the output volume using the (0-3.3v) DAC on my microcontroller. I'm wondering if there is a simple modification I can do to this ...
0
votes
1answer
87 views

Not functioning Class-D Stereo Amplifier circuit

I am connecting a circuit for Texas Instruments TPA3125D2 Class-D Aplifier. Datasheet here: http://www.ti.com/lit/gpn/tpa3125d2 The circuit design is here: The circuit that was tested is not on ...
6
votes
5answers
2k views

Circuit to “zoom in” on mV fluctuations of a DC signal?

I have a signal that is roughly 0.2V + noise fluctuations of order 0.1-2 mV. Ideally I want to amplify this signal such that the mV fluctuations become about 1V. In other words I want to amplify the ...
2
votes
1answer
87 views

Output Filter Components Breaking Class D Amplifier Chip

Hi I am designing a class D amplifier PCB using the TPA3122D2 amplifier chip. I am planning to base my circuit on the schematic from the evaluation board: I bought components of the same values given ...
0
votes
1answer
141 views

How do I calculate expected output voltage of car audio amplifier with given conditions?

I have a 4-Channel Amplifier rated at 800 Watt RMS per channel @ 2 Ohm load. Channel 3 and 4 are preset to operate a subwoofer speaker while Ch 1 and 2 are set to operate mid-range speakers at ...
0
votes
2answers
50 views

What is the base current of a class ab amplifier with darlington pair configuration

I am trying to design a 3 stage amplifier using transistors, 2 pre-amp stages using class A configuration and an output stage class AB. I have built the class ab amplifier with a darlington ...
0
votes
2answers
68 views

Accelerometer Sensor Output Impedance

I am looking into purchasing a TE 810M1 Accelerometer and had a question regarding the resistor's value for amplifying the sensors output. Here is a photo of the sensors electrical properties: The ...
0
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0answers
55 views

Replacing AC transformer

I've encountered a problem while replacing the AC transformer of a soundsystem composed by 3 loudspeakers (1 bass loudspeaker (4Ω5W) and a couple of highs(can't open to see the specs of these)) and a ...
0
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2answers
128 views

Purpose of attenuation before op-amp input

What is the purpose of putting attenuation circuit before op-amp input? I cant find the actual reason for this topology. Is there any reason behind it? Why we need to attenuate the incoming signal but ...
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votes
3answers
111 views

Is it possible to wire car speakers straight to a 3.55 mm jack? [closed]

Is it possible to re-wire car speakers (model JBL GT7-5) to a headphone jack (3,55 mm stereo plug) directly without an amp? And if not, what do I need to-do? This what I know about the speakers: ...