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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1answer
20 views

Calculate necessary attenuation (in dB) to achieve a given output voltage

I need to connect an audio unit with an output of 2V (and an output impedance of 560 ohms) to an amplifier with input sensitivity of 0.985V. Since the 2V output is too high for the amplifier, I need ...
0
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0answers
22 views

Use wall adapter to replace 8 AA battery pack [duplicate]

I'm fairly new at electronics as a hobby and would like to use a wall outlet adapter instead of a battery pack. The instructions say to use an 8 AA battery pack and I would need an equivalent power ...
1
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1answer
38 views

Advantages and disadvantages of reading a current-sense amplifier with different gains on I2C

I am writing an I2C wrapper for the MAX9611 chip. For the current-sense amplifier (CSA), according to the datasheet there are 3 selectable gains (1x, 4x and 8x): When I read the 12bit ADC registers ...
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0answers
40 views

Current across high speed mechanical switch contact even if it can’t be measured?

If I am cycling a mechanical switch at a frequency higher than the bandwidth of a current amplifier and biased using a DC source, is current actually flowing across the contact? The following ...
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1answer
43 views

Do power cords come with Amps [on hold]

I two amps that were my dads. An AER 60 Compact and a Henriksen Jazzamp. I don't see any power cords for them or compartments that might hold them. Do these type of amps come with the power cord when ...
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2answers
209 views

Identify this component?

I refer to the two round yellow-ochre things mounted on the blue capacitors. They are coupled in series from a sold-state power amplifier stage, and the capacitors AC couple to the speaker load. The ...
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0answers
49 views

Sedra & Smith Microelectronics 7th edition Problem 7.8

The answer is 0.712V, but how?
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2answers
62 views

What happens if I change the value of a coupling capacitor in a tube pre-amp

I own a Blackheart BH1H amplifier and am considering making modifications to change its sound. The schematic can be found here One change I have seen suggested is to change the value of C2 from it's ...
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0answers
54 views

Which branch of EE would audio I/O interface design be? [closed]

Hello everybody and thanks for clicking on this question. I am a junior year electrical and electronics engineering student and I am undecided on which specific branch of EE to pursue for my degree. ...
2
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2answers
56 views

What limits length of wire connecting audio amplifier to speaker?

Let's say I have LM386 or some other audio amplifier. What determines the length, resistance, capacitance and inductance (if L C parameters matter) of the conductor that carries the output of the ...
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0answers
20 views

HTC 10 DAC/amp specifications

I'm going to be doing a final year project revolving around music production and DACs are pretty important. Not going to go into detail (unless this question requires it) what the project is but I ...
3
votes
2answers
88 views

Why do we have 2 representations for load (shown below) in a power amplifier?

OR I get confused when i see two different ways to connect load resistor in a power amplifier. Why do we have two such representations (RL in series with collecor Vs RL connected across collector ...
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1answer
52 views

Positive Feedback Of A Summing Amplifier

I've recently come across a topic that has not been covered in my studies (or at least not as yet). It's positive feedback of an amplifier. I have been reading this link on positive feedback. From ...
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1answer
54 views

Op Amp DC multiplier

Is there a circuit (that only uses op-amp and resistors) that performs multiplication between two DC input signals v1 and v2? Similar to the Summing Amplifier but with multiplication.
11
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4answers
1k views

Is the input impedance of an operational amplifier (op amp) infinite or zero?

Ideally, the input impedance is infinite. But, in calculating the input resistance (Rin) of a difference amplifier, the author took the concept that the two input terminals are short circuited, which ...
0
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4answers
73 views

Push pull amplifier

What's the aim of using a push pull amplifier instead of nothing? I mean, what is the difference between connecting the input signal to the final load instead of putting a push pull amplifier between ...
3
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2answers
98 views

Stability of Constant Current circuit

we are developing constant current circuit with "High" current rate, about 3A. We are testing the second prototype, the circuit is this: Behaviour its ok, but we have observed, when we set high ...
0
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1answer
50 views

Applications of transistor feedback

I saw the following circuit in an electronics exam. I think the feedback network consists of a transistor (M3) and a resistor (Rf) and the feedback type is current-current; Is this analysis correct? ...
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0answers
28 views

Tda2009a amplifier circuit isn't working

So I have testing out the tda2009a circuit on a non soldering breadboard and no sound come out of it whenever I test it. The chip is new so it shouldn't be broken. I don't know what's going on. Pleas ...
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0answers
26 views

3 phase motor amplifier

I have generated a 3 phase variable frequency single. Now I want to drive a motor. Is there a type of ready built amplifier module available to drive a motor from a 3 phase sine wave input? All the ...
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1answer
78 views

Which part of this circuit plays the role of filtration?

Can anyone say which part of this circuit plays the exact role of filtration and which part plays the role of amplification? How can I find and learn the calculations related to these parts? It's ...
2
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1answer
87 views

Will this phantom power circuit work?

I'm designing a musical instrument in which two oscillators (one based on a Quad Nand gate, the other on a 555) are controlled by a signal from a condenser microphone. At the moment the mic is being ...
0
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1answer
89 views

Voltage divider before the input of an LM324N used as a comparator

simulate this circuit – Schematic created using CircuitLab I am designing a driving system to control some servomotors, and since my microcontroller can not drive enough current, I had thought ...
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1answer
77 views

Lock-in Amplifier

I am a physics student currently trying to make measurements of Semiconductor saturable absorber samples. In my setup laser light reflected from the structure falls on a Thorlabs DET100A/M - Si ...
2
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1answer
33 views

RFC realization for bias of microwave transistor circuits

I saw the following configuration for the bias circuit of some microwave amplifier circuits. I think in the left figure the RFC is realized using a quarter wavelength short circuited stub (because of ...
0
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2answers
50 views

AD620: AC Input Generating DC Output

I've been using the AD620 to offset and scale up a tiny AC signal for my project. The AD620 is set up in the following way: Rg= 6.8kOhms (between pins 1 and 8) Vin = 0.123V rms AC signal (pins 2 ...
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0answers
46 views

How to increase the sensitivity of this EMF detector (Arduino based)? [closed]

I built this simple circuit that I found on the web to detect electromagnetic field signals: Basically, an antenna is plugged in to both the Arduino's analog input (directly) and to the ground (...
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0answers
23 views

Parameters of a current sense amplifier

I am trying to select a current sense amplifier for my design. My design parameters are :- Vrail:- 9V to 21V ILoad :- 20A(max) When I look on digikey, http://www.digikey.com/product-search/en/...
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2answers
96 views

Op amp amplifier with capacitor [closed]

What happens when the resistors of an op amp amplifier circuit are replaced with capacitors? Or inductors? What is the frequency response of such an arrangement?
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3answers
54 views

How can i extend Bluetooth range at maximum?

I want to extend at "maximum possible" the range of my Bluetooth Low Energy chip, Nordic nRF51822. I have no limits of space, transmit power or energy requirements so i can use whatever i want. I was ...
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0answers
37 views

How to feed audio signal to car stereo volume controller (LC75421M)?

I'm trying to hack AUX input into car stereo with tape mechanic. I managed to identify the most important circuits. The idea was to use tape mode to amplify custom audio input. The original wiring ...
0
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0answers
25 views

Class D Amplifier

For a piezomotor control I've used a class D amplifier TAS5162. PWM is provided directly to it with a microcontroller. I've made the same circuit as mentioned in the datasheet but instead of getting ...
1
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0answers
49 views

Isolation Amplifier Design Issue

I modulate input signal with triangle wave to create PWM signal. When I am creating triangle wave I use astable multivibrator and integrating circuit. unfortunately there are offset at my triangle ...
0
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1answer
140 views

What are the purpose of those resistors and capacitors network before the mic jack?

I was looking at M851 motherboard schematic to learn something from these documents and saw an interesting circuit for microphone. look: 1- What are the purpose of those resistors and capacitors ...
0
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1answer
63 views

How to maximize the voltage range using an operational amplifier (differential amplifier)?

I'm trying to maximize the voltage range using voltage dividers and operational (differential) amplifiers, but am not able to do it. I do not have an electrical engineering background, but my project ...
1
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2answers
134 views

Decaying envelope when audio passes through diode

This is a basic question about passing AC (audio) signals through a diode. I'm trying to use an audio signal to power an LED (which in turn heat-shrinked to an LDR) in order to control the behaviour ...
1
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3answers
126 views

50W Amp for 15W Speaker

I am building a portable speaker and I am looking for a decent amp for my two 15W Phillips speakers. It is tough to find an amp that is efficient and cheap so I was wondering if there is something ...
1
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7answers
88 views

Why should we set input source equal zero for calculating output resistance of common source amplifier?

This lecture (page 10) gave derivation of common source output resistance. What I don't quite get here is why we should set the input source equal 0 for calculating output resistance. Could anyone ...
1
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3answers
146 views

Open circuit resistance in common gate amplifier

I am reading about common gate amplifier on this page and there is a small signal model that I am a bit confused. The common gate amplifier and its small signal model is shown below. As you can see ...
0
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2answers
69 views

Does audio OP-AMP circuit needs output capacitors?

I saw schematics with and without output capacitors. So in the end - do you really need capacitors in the output? I am using OPA2134 operational amplifier. I plan to use it both as headphone and ...
0
votes
1answer
116 views

How to amplify a 25khz square wave that goes from -3.3v to +3.3v so that the amplitude is doubled

I have a 3.3v power supply (lithium ion battery) and am using a TI MPS430G2553 chip to generate a 25khz square wave using 2 PWM pins and a push-pull setup. This square wave goes from -3.3v to +3.3v. ...
1
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1answer
85 views

AGC with multiple op-amps

I have four op-amps that are each amplifying signals from four different microphones. All of the microphones are recording a single source, but the location of the source moves, so the outputs from ...
0
votes
1answer
67 views

How to connect a headphone jack to this lm386 [closed]

I would like to attach a headphone jack to this board but I'm a bit confused as to how since the jacks I find have 5 pins but this only has 2 places for the headphone cables. Thank you in advance ...
1
vote
4answers
371 views

Op Amp in buffer configuration is decreasing output voltage

I have a 4.24V DC signal which I have to apply a buffer in the purpose of have a high impedance between the 5V signal and Op Amp output. My circuit is like following: The problem is that my output ...
0
votes
3answers
80 views

LM386 no output with input signal below 2V

I'm trying to implement volume control using a digital potentiometer (LM386) and audio amplifier (MCP4131). The way I have it setup, I'm outputting square wave audio signals out of a PWM pin on the ...
0
votes
1answer
91 views

Vout of differential amplifier as Vref of comparator

simulate this circuit – Schematic created using CircuitLab I am a beginner at circuit design, and I am having trouble using the Vout of differential amplifier as Vref of comparator. The other ...
0
votes
2answers
79 views

Speaker BJT Amplifier - very low gain

First of all this is not related to a HW or anything; I just wanted to build an audio amplifier and test my skills. I really don't see why my design is not working as intended, without the speaker ...
0
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0answers
83 views

Current Amplifier using bjt [duplicate]

The output current through V5 is supposed to be 1A and I am getting around 460μA. TIP122 and TIP127 have minimum current gain of 1000. So the current entering each darlington transistor should be ...
1
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2answers
62 views

Pre-amplifying an electret mic already in use

I want to remove the DC component and boost to a line in level the mic signal of a regular headset plugged into a mobile phone while still allowing the mic to be used by the phone at the same time: ...
0
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0answers
72 views

Guess about the function of this circuit diagram

In a HiFi amplifier from T&A I have found this strange circuit and I haven't any idea what it is for. Maybe for reduce some specific noise or any strange thing for hifi purpose. Anybody seen this ...