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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)

2
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2answers
78 views

Reverse engineering old record player schematic

So this is a loaded question I know, but I'm stuck and I don't know where to go from here... My mom has a super old record player. It's build into a bright orange suitcase which is pretty cool. We ...
0
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1answer
18 views

CD4011 Oscillator Square Wave Output Fed to Transistor Audio Amplifier; Volume Control Question

I built an audio frequency square wave oscillator using 3 gates on a CD4011 quad NAND gate IC. I then fed the output of the oscillator (pin 11) to a very basic "push-pull" transistor amplifier on the ...
-3
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0answers
25 views

Multistage Audio amplifier with gain 175 [on hold]

I need to Design the audio amplifier with following specifications . I am going to design for the first time and I don't know what sort of transistor should be used how should I start . Any tips . ...
0
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2answers
48 views

How to mount four 6-wire 10V load cells on Arduino or Raspberry Pi?

I want to connect four 6-wire load cells (Tedea Huntleigh Compression & Tension Load Cell 300kg, 15V dc, IP67, product page and datasheet) into an Arduino or Raspberry Pi and get four independent ...
0
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0answers
27 views

Reusing speakers from an old laptop: how to amplify them?

I would like to reuse two pair of speakers got from an old ASUS 1201T laptop. Since I don't know the specifications of the speakers, I looked in the datasheet of the Realtek ALC269 sound card and ...
0
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1answer
56 views

Class D Amp headphones grounding circuit

I am having a problem with some of the class d amps I've played with (PAM8302A), and it seems like this article here describes my problem: https://www.edn.com/design/analog/4313726/Add-headphones-to-...
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2answers
40 views

Circuit Choices for AmpIifier Input

i have breadboarded a TDA2050 amplifier, using this schematic i get good sound intensity with a half acceptable quality. the down side is the constant noise and humming. i have found a possible ...
0
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0answers
63 views

I cannot figure out what kind of transformer this is [on hold]

So I was told this is from a welder but I would like to us it for fractial wood burning but I cannot figure out what kind of transformer it is and how to do it, all the videos use microwave ...
0
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1answer
94 views

Inductance of air core coil with small diameter

I have some legacy circuits with air core inductors (copper) w/ 19 turns, SWG = 24, dia = 3.20 mm, Length = 12 mm. The measured inductance on a good instrument was 80nH/13.7 milliohms & 93nH/13....
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0answers
37 views

How many bulb and Fan will run in 3AMP light? [on hold]

In 2BHK flat, How many bulb and Fan will run smoothly. Is there any way to check?
4
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2answers
2k views

I found an audio circuit and I built it just fine, but I find it a bit too quiet. How do I amplify the output so that it is a bit louder?

I want to try something audio related and found the following circuit from technoblogy I built it and loaded a sound clip. Everything works fine, but I found it a bit too quiet and I want to amplify ...
0
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2answers
87 views

Shutdown amplifier when headphones are connected

I'm designing a board for a diy synth, one of the circuits consists in a audio amplifier that drives a small 1W speaker. The amplifier takes the signals from a Raspberry hat(a Fe-Pi Audio V2) and I ...
13
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3answers
10k views

What is a PA/LNA?

I saw a comparison of two similar radio receiver modules. They used the same IC, but one had a greater range due to the inclusion of a "PA/LNA" which I understand to be an abbreviation for "Power Amp /...
0
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0answers
44 views

Distortion via Powered Speakers and not in Headphones - 1 Transistor Amplifier

I'm trying to make this NPN amplifier circuit work for my battery powered computer speakers. This circuit works fine if i connect headphones to it in output, but has distortion when connected to a ...
0
votes
1answer
34 views

Why does the output voltage of my linear gain amplifier depend on the JFET gate voltage?

I am trying to build a linear gain voltage controlled amplifier using an N-channel JFET as a voltage variable resistor (see circuit below). As the circuit is set op now, I would expect Vout to be ...
1
vote
1answer
41 views

HFA3096 transistor array breakdown voltage

In the book Learning the Art of Electronics, one of the labs is to build a differential amplifier with a CA3096 transistor array. The author admits that the chip may be difficult to find and gives the ...
0
votes
4answers
66 views

Op Amp: signal measurement that is below its common mode input range

I was wondering, how is possible to use an op amp, which its common mode input voltage is (V-) + 0.2V to (V+) - 0.2V to measure signals as low as 10mV for example? I'm looking for an ...
2
votes
1answer
52 views

Measuring integrated current

I want to measure the amount of light striking a photodiode in a specific time window (about 1ms). In this window, we get \$10^6-10^7\$ photons, which get converted into electrons with about 80% ...
0
votes
1answer
202 views

How do calculate / determine the reference voltage for the error amplifier of my analog PWM generator for a 0-100% duty cycle

For a school project I am building an analog PWM generator with 0.1 to full-scale linearity and a duty cycle 0-100%. Powersupply is 5 Volt and 100% is equal to 5V at the output. The frequency 1 Khz. ...
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0answers
46 views

Old tube amp from a Baldwin organ [closed]

Hello to all and thanks in advance for any help .. ok well I have this tube amp its complete I have everything out of the unit .. I'm very curious about making this I to an audio amp for my home ...
1
vote
1answer
88 views

Sensing high differential voltages using operational amplifiers

Is there any solution to sense high differential voltages using operational amplifiers (without using resistive voltage divider) ? The input voltage range is [-30, 80] Volts. I've searched on all ...
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2answers
973 views

A basic level question about grounds in a differential amplifier circuit

As far as I know, voltage is a defined with respect to a common ground in circuits. So if there is a source and a receiver/amplifier; then they should have a common ground if we want to talk ...
0
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2answers
92 views

High Input BJT Differential Amplifier

This is a basic differential amplifier. I want to modify it in order to have high input impedance (a few \$M\Omega\$ from DC to at least \$200~kHz\$) I thought about replacing the CE pair input with ...
0
votes
1answer
47 views

MONO output from STEREO amp (T-Class)

I have ONE Boston Acoustics Micro90X Speaker (for 15-125 watt amps), and a Topping VX1 2x25W Class T Amplifier (notionally 2 x 25 watts) that I don't currently use. I thought both of these gave ...
0
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2answers
119 views

How can I calculate V1 and V2 in this circuit?

How can I calculate V1 and V2 in this circuit? This is what I tried so far: Calculate the voltage of R5 through voltage divider but I didn't find the way, I was looking about second OA circuit but ...
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0answers
34 views

Differential amplifier Vout [closed]

I'm just learning about differential amplifiers. In this video, he says Vout = V1 + V2, and if the resistors are set correctly, Vout = A(V2 - V1) Why is Vout = V1 + V2?
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0answers
23 views

Unbalance effect in differential amplifier

Consider we have the below differential amplifier : Consider that the two resistors R2 are not balanced and the unbalance in this resistors is represented by delta R2. The common mode rejection ...
0
votes
1answer
94 views

Equivalent noise resistance(s) - 2 stage amplifier

I came across this question in my textbook: The first stage of a 2-stage amplifier has a voltage gain of \$150\$, an input resistance of \$1500 \Omega\$, an equivalent noise resistance of \$700 ...
0
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0answers
19 views

Calculate Capacitor mf for PAM8402 Amp Powered From RPi

Trying to figure out what capacitor mf I should use for a 5v PAM8402 audio amp that is powered by a Raspberry Pi. When the amp is first turned on it triggers the Pi's low voltage warning. I'm using a ...
5
votes
2answers
19k views

My amplifier produced a negative gain when it should be positive. Why?

Disclaimer: I am a Mechanical engineering student and I don't have a huge background in electrical engineering. In on of my lab classes, we just dealt with the response of amplifiers to a variable DC ...
1
vote
2answers
91 views

Trouble with optocoupler 4n35

I'm trying to ride a full bridge inverter using SPWM to control the MOSFETs, the signal SPWM that I use to control the MOSFETs comes from an NI elvis, but it only provides 5V and I know the fact that ...
2
votes
1answer
48 views

Variable gain amplifier output appears on circuit positive and negative supplies

I am trying to use the analog devices AD600 in a simple sonar system. However, the performance of the chip is severely degraded because whenever the chip's output is nonzero, a portion of that output ...
0
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0answers
31 views

LM4890 amplifier and CR1616, how to improve power consumption?

I'm a hobbyst trying to design a simple circuit for amplifying the PWM audio output of an ATTINY85. I'm using an LM4890 (1W amp) and a 1W microspeaker. The problem comes when I supply 3V with a small ...
0
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0answers
36 views

Three level PWM modulator circuit feedback simulation

I'm trying to design a three level PWM circuit with feedback and i'm struggling to understand the feedback aspect. The design is based on this design by Texas instruments and modified to suit three ...
3
votes
1answer
104 views

A question about understanding a BJT differential amplifier?

I'm trying to understand how a differential amplifier rejects common mode noise and amplifies the differential/normal mode noise. For that I use the following circuit topology and simulation: When ...
1
vote
2answers
94 views

need circuit help with headphone amplifier 'thump' and other issues

This is my first post and I have a million questions. I hope some kind souls out there will not mind my noobness and be able to guide me any way they can. Firstly, I have a headphone amplifier ...
2
votes
1answer
98 views

High voltage high speed low current amplifier

I want to design an amplifier that can take an 8MHz signal (even square) with an amplitude of only a few volts (1-3V) and amplify it up to 160V but I only need it to deliver about 60mA. I also want to ...
0
votes
1answer
104 views

Actuating Pencil To Draw Waveforms

I am looking to make a pencil whose tip moves to create a waveform as you move it across the paper.In essence, I want to be able to record a sound and then play the sound through the pencil whilst I ...
0
votes
1answer
92 views

Isolated High Voltage Amplifier Idea

Test laboratory of our factory asked me to design an isolated high voltage amplifier. Here are the requirements: The circuit will be built with transistors and passive components in the lab. (No IC ...
0
votes
1answer
51 views

How can a guy calculate the second collector current from this circuit?

This is an audio amp that we built for a project. I can easily find the first collector current from the first transistor by multiplying it with its Beta(200) and since the first transistor is beta ...
-1
votes
1answer
57 views

Audio amplifier using LM386L

I am a student and I am trying to build an audio amplifier. I wanted to ask if there's any way to replace capacitors with different (some in pF). If it could be possible, let me know. I'm using 9V ...
2
votes
1answer
62 views

How to measure 0.02V to 0.18V audio signal with arduino?

I have a Sony STR-DE845 home theater amplifier with 8 Ohm speakers. I want to measure the voltage sent to the speakers to infer their volume using an Arduino. The AC voltage measured across a speaker ...
1
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1answer
95 views

Buffer, amplify, filter, sample - In which order?

I'm trying get an audio signal from a high impedance source (guitar or mic) to an ADC. Some casual research suggested that I should filter my signal before amplifying it. My current mental design is:...
1
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4answers
4k views

Distortion in TDA2030 circuit

I looked at a friend's guitar amplifier which wasn't working, the problem was clearly (because it fell off) a broken IC (TDA2030AC). After replacing it, the amplifier started working again but when I ...
0
votes
1answer
90 views

High-voltage (HV) messing with my transimpedance amplifier circuit

I have a transimpedance amplifier circuit that takes 100kHz small current and gives the voltage output proportional to current amplitude. Everything works properly when nearby HV circuit is off. When ...
4
votes
4answers
2k views

Noise from solid state rectifier in tube amp

Recently I was talking to a friend about solid state rectifiers in tube amps. He told me that solid state rectifiers induces noise in the power supply, because the breakdown current of the silicon ...
4
votes
2answers
173 views

DC input on op amp integrator

I am trying to integrate a DC tension with a classic op amp integrator. The problem is : when I simulate my circuit on LT Spice, the output will always be equal to the VEE tension of the op amp ...
0
votes
4answers
94 views

Nonlinearities in Fully Differential Op Amp

I am trying to construct an amplifier circuit using a fully differential op amp (THS4503) to interface with an ADC (ADS5232). I will be reading a 0-5V sensor, which needs to be converted to a 1Vpp ...
0
votes
1answer
83 views

amplifier for 10V LED dimmer control using Raspberry Pi

My problem is I need to have an amplifier circuit design - schematic + components BOM with specific model information that is able to provide a dimmable output signal (Vout) 0.2-10V <0.8A for a set ...
1
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0answers
53 views

Amplification problem

I am using an instrumentation amplifier AD620ANalong with another amplifier TL084CN in series. Both have gains of 100 which essential for me since the input is in microvolt range. The frequency is 87 ...