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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16 views

The GDP2846A module has an in-built 2W amplifier which is fine for a small speaker but not for a pair of headphones. I've thought of directly taking the DAC outputs to the headphones and call it a day ...
26 views

Drop in Amplifier High Frequency Gain without Large Power Capacitors

I have designed a simple class AB audio amplifier circuit which can be seen below. I am simulating the amplifier and have used a single, 100uF capacitor for C3 and C4. The simulation is being run ...
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I don't understand JFET/this diagram Associate CET study guide

0 I need help understanding JFET amplifier circuit I have a lot of questions that maybe basic questions I'm sorry. This is a N-channel Jfet so it has negative voltage but what does that even mean “...
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20 views

How to find noise sources from noise figure data?

An amplifier datasheet provides noise measurements that show it has a noise figure of 3dB for R_s = 100Ω and R_s = 10kΩ (same noise figure for both values of R_s) at T=300K and f=10kHz. I need to ...
124 views

How can negative feedback reduce distortion if A*beta>>1?

I have read that negative feedback reduces distortion (frequency, amplitude, phase) because if $A \times beta >>1$ the transfer gain will be $(A/(1+A*beta)) = A/A \times beta=1/beta$. Which ...
1 vote
43 views

LTspice-RIAA-simulation not working out

I'm trying to simulate a RIAA-phonograph-preamp since I want to build a phono-preamp. I've built everything according to the data provided by LT for the LT1115. But my simulation seems to not be ...
1 vote
73 views

How do I compute the power consumption of an audio amplifier?

I intend to use this audio amplifier in my project : PAM8019 It has two analog inputs : left channel and right channel. It has two analog ouputs, which are the amplified inputs. Let's say I follow the ...
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32 views

How to disable Bluetooth temporarily for line in to work in mini hifi amplifier TDA7492P? [closed]

The TDA7492P, a mini hifi amplifier with Bluetooth and line in does not allow line in, it jumps to Bluetooth soon after the start and blocks the line in signal. It goes like this: Power on line in. ...
46 views

Output reflection coefficient of a power amplifier

I'm struggling to understand the implication of a poor large signal reflection coefficient at the output of a power amplifier. I designed a power amplifier and checked the large signal S22 (for the ...
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44 views

IR remote code amplifier

I am interested in amplifying output mod signal of my tv remote in order to use a higher power led/vcsel. Now, it should be as simple as cutting the emitter led and putting a transistor that would ...
44 views

Passive equalizer design

I have circuit feeded from a 3.5 mm jack through a JFET common-drain buffer then i need the filter this audio input to pass bandwith 400-19600 Hz. I can do this with RC bandpass filter but then I need ...
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38 views

Speakers stopped working, make cracking sound and are very quiet, how do I fix them? [closed]

I have made photographs of the PCB inside the speakers, 'laser' integrated amplifier and speaker system. If you see any obvious problems please let me know. It is frustrating to have a shiny, ...
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42 views

Active Speaker Hiss [closed]

I'm trying to figure out why my Mackie SRM350v3 has a lot of white noise and digital whine (100Khz) coming through. The hiss is not dependant on the volume knob and I can hear changing in the digital ...
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23 views

MPQ3904 LTSPICE Model

I'm trying to do some LTSPICE simulations using a MPQ3904 NPN BJT. Of course this specific model is not in the LTSPICE library. I tried to look up possible models online but I can't find anything. The ...
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44 views

Line Level Amplifier [closed]

I'm looking for a circuit that will take an audio signal in at any level (higher or lower than line level) and only output line level. From what I have seen online most of the sites I have found take ...
63 views

Isolate digital switching from audio circuit

I'm using an L298 H-Bridge to drive a DC motor. The motor is spinning a magnet across a guitar pickup at ~30 Hz. That signal is then amplified and sent to a speaker. However, the output signal also ...
117 views

Does anyone know why this diff amp isn't working?

simulate this circuit – Schematic created using CircuitLab I'm new to electronics and I've been figuring out how a diff amp works. I followed a schematic I found on YouTube. Basically, as V3 ...
64 views

How does the common emitter configuration offer higher output impedance?

I know that the base-collector region is reverse biased and because of that it offers high resistance but it is the resistance due to biasing. In a video, the person was explaining the hybrid-pi model ...
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29 views

Where To Connect Wires on Pin Out

I am very inexperienced in wiring. Where do I connect the wires from my trans-impedance amplifier to my DAQ to measure the voltage out and also to apply a voltage. I don't understand why there are ...
85 views

How to properly couple DC in this biased headphone amplifier design on power-up?

I am a self-study noob to electronics (and audio electronics) but diligently learning every day :) Some things I understand well, others I'm fuzzy on. This device is a headphone amplifier using NE5532 ...
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81 views

Where can I find large thru-hole heatsinks like this? [closed]

I'm doing a project with an OPA541 amplifier, and I need to find a heatsink similar to the one in the pictures: But I only found small ones with a screw hole and legs for soldering, none of the large ...
42 views

Current Shunt Amplifier Problem (MAX49921)

I'm currently trying out the evaluation kit for the MAX49921 from Maxim, and I'm having a few problems with it. First thing to note is that my board appears to be an issue a board, but all the ...
64 views

Picking up ultrasonic signals on a hydrophone

I bought two Aquarian H2A (3.5mm version, not XLR) hydrophones for receiving faint ultrasonic signals (29 KHz) being generated by an underwater sensor node. I am running into some issues. I tried to ...
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54 views

Does an amplifier consume any power when nothing is connected? (GPD2846A built-in 2W amplifier) [closed]

The GPD2846A module has a built-in amplifier into it. However, I want to use it with my headphones which don't require 1-2W (they are definitely going to distort sound and possibly be damaged). So I ...
401 views

Amplifier with selectable inversion?

Two inputs: Signal: 0-5 volt analog voltage Direction: Standard TTL logic Output: A single analog voltage from -10 to +10 volts When Direction is low, the Signal is amplified and inverted, so that ...
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1 vote
61 views

Class AB RF Amplifier with only one active device

I'm designing an amplifier for the 420-440MHz band. I'm looking at using the following part from Ampleon: BLP15H9S100. I'm new to doing RF amplifier work and I've been going through the design process ...
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45 views

The output of PI controller using opamp is not working [closed]

I am designing a closed loop system for dc-dc converter for that I am using error amplifier and pi controller. For error amplifier and PI controller I am using OP177A opamp. The error amplifier ...
1 vote
33 views

PSRR of an amp + ADC input stage

I have an input stage that consists of an amplifier then an ADC. The op-amp and ADC are powered by Buck voltage regulators. I want to measure the PSRR of this stage, so I am planning on breaking the ...
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33 views

How to wire a dynamic mono microphone with PAM8610 stereo audio amplifier

I am trying to make a audio amplifier with PAM8610. I have a dynamic mono microphone. In the PAM8610 official file they say that "To use the PAM8610 with a single-ended source, acground the INP ...
75 views

What would the output impedance of the circuit below be?

My analysis is as follows, the auxiliary amplifier with input Vb is being used to sample the output current of the main amplifier (NMOS on the bottom) and return a voltage to its gate. So it is ...
500 views

Is it possible to use CRT tubes for audio amplification?

I was wondering if it's possible for me to use the tubes in an old CRT TV to build an audio amp (specifically a guitar amp). If not, would I be able to salvage something else (like an old radio) to ...
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39 views

Common emitter amplifier with low impedance

The following schematic shows a common emitter amplifier driving a resistive load. The common emitter has a high output impedance, is it possible to use the amplification achieved with the common ...
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1 vote
115 views

How to calculate the output resistance of the CE amplifier, which has only a coil in its collector?

In order to be able to match the impedance, it is necessary to know the output resistance of the amplifier. In radio frequency amplifier circuits, there is usually a coil in the collector instead of a ...
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163 views

I'm desiging a class AB amplifier with class A preamp, what are the problems with my design?

I'm attempting to design a class AB guitar amplifier with a class A preamp. I'm a novice and this is the first actual project I'm attempting. What are the possible caveats, as well as my choice in ...
158 views

Electrical amplification of 10ns pulses without "ringing"

I have an expensive arbitrary waveform generator (AWG) that can create very clean arbitrary pulses. I am producing gaussian pulses from this AWG that are about 10ns wide, which look like this on a ...
78 views

Three stage BJT Amplifier

I'm working with a three-stage BJT amplifier that takes an input from a DAC with a full-scale output voltage of 0-2.5V. I've been told from probing the output the gain is somewhere around 100. I was ...
75 views

Bidirectional voltage-to-current converter

How to make the following voltage-to-current converter bidirectional, so that bidirectional current can be driven through the load?
37 views

What is the recommended Amplifier/Receiver (AVR) for my Surround Sound 5.1 Speakers Configuration?

Here are my speakers & subwoofer configurations, wondering if anyone can help me suggest a minimum AVR configuration I should go with: I am looking at Harman/Kardon or Denon AVRs. Little back ...
37 views

voltage amplifier design feed by current source

I want to connect electret microphone with long wire to receiver. Usual way is to use balance line technology, but it can be expensive, then I've opted to use CCLD Constant Current Line Drive ...
675 views

Headphone output - what is the function of these resistors going to ground between the decoupling capacitors and headphones

The Korg Monotron Duo synth uses the TPA6111A2 headphone amp. The circuit they use is largely the same as the one from the datasheet - except for R78, the 470ohm resistor going to ground right after ...
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What would be the amplification circuit for PP02 sensor using LM324 pressure sensor?

I am planning to use the PP02 Omron pressure sensor. The user manual of the sensor (Usermanual link) suggests using LMV324 type of instrumentational amplifier with four op amps within in the schematic ...
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I was looking at the LT6118 datasheet, since the TI amps (like te INA381) I am used to are not available. They mostly do the same thing, and probably are intended as direct competitors, IMHO. The job ...
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Having a hard time identifying this component; maybe the logo can help

Does anyone have any idea what this part Q6 is? It appears to be some type of SOIC 8 FET. Logo on the device:
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54 views

Package & Variable Gain Amplifier Identification

I am trying to identify an unknown wideband VGA whose markings were scratched off. It is apparently a 5W amplifier, drawing 1A @ 5V power supply, with analog gain control - using a 10k potentiometer. ...
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1 vote
71 views

Common source amplifier analysis method?

When I make a DC analysis for the following circuit the capacitors are open circuit. But what if C1 does not exist, what is the effect in DC analysis? Does the signal generator still exist or should I ...
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1 vote
55 views

What happens if you go below the minimum common mode voltage of a current sense amplifier?

This might be a simple one, but I can only seem to find information on going above the common mode voltage (VCM), not below it. Obviously going above the VCM upper limit will damage the device. I'm ...
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210 views

I am having trouble measuring the amplitude of a 97 MHz signal with an oscilloscope with a bandwidth of 100 MHz

First, I designed a Colpitts oscillator with a frequency of around 94-97 MHz. I added a common emitter amplifier to the design to increase the output amplitude of the oscillator, then I connected the ...
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1 vote