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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38 views

How does an speaker amplifier have to be build for a given DAC output signal?

I am working on a project "cat projector" which shall "shout" at the cat when she jumps on the table in the living room. For the logic I use an Arduino board which plays/streams the sound at 22.1kHz ...
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1answer
34 views

Design of 5 - 15 MHz Voltage Preamplifier

I'm trying to design a power amplifier for the HF band to drive an inductive charger. The stage I'm working on now is a voltage preamplifier which needs to be able to amplify 1 Vpp to 10 Vpp. The ...
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0answers
37 views

Are these amplifiers LT1991 and LT1995 good for prototyping?

Do the above amplifiers fullfill these requirements? ISO 13485, EU-Directive 93/42/EEG Medical Devices, ISO 14971 Risk Management, IIEC60601-1 electrical and EMC tests I want to get the best ...
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1answer
29 views

Buffer amplifier

I have a buffer amplifier that is single supply 0-10v Lets say I give it an input (sine wave 0-10v Vpk-pk) and added a dc level-shifter to shift the input signal up by 0.5v (0.5v-10.5v sine wave ...
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2answers
37 views

DC - DC Amplifier for Piezo Buzzer

I have a Raspberry Pi outputting a 3.3v DC square wave that I'd like to be able to amplify to just under 20v, the maximum the piezo can handle. Just to clarify, the piezo does not have an internal ...
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3answers
394 views

Which Amplifier Should I Use After my DAC (what are I am doing wrong)?

I am working on a project "cat projector" which shall "shout" at the cat when she jumps on the table in the living room. For the logic I use an Arduino board which plays/streams the sound at 22.1kHz ...
2
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1answer
288 views

What is an antenna amplifier ? How does it add gain?

I don't know what exactly does antenna amplifier mean. Is it possible to increase the gain of a Tx antenna ? Where do I connect the antenna amplifier to it ? If, for example, the Tx has a power of 20 ...
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2answers
114 views

Is it possible to amplify near zero signals?

Is there an amplifier has an ability to amplify any signal down to -500 dBm? If there is not, can it be possible? If it is not possible, what is the weakest ever signal that can be amplified?
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1answer
66 views

Just I want to understand gain, power, link budget

I am a beginner, I am confused about calculating the nessecary gain and power and sensitvity to overcome path loss at certain distances. the first thing what does gain mean ? I am not talkink ...
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1answer
46 views

If I connected N numbers of amplifiers each have X gain 'dB“ and Y power ”dBm", how to calculate total gain and power?

sorry for bad description, I am a beginner. my question is just for knowledge and I did not test anything. If I connect for example 3 amplifier , each one has 60 dB gain and 15 dBm power. can we ...
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1answer
44 views

What frequency range is acceptable for a speaker in an audio amplifier

I am building an audio amplifier using a lm386 amplifier with a 12 volt supply driven from a headphone jack. I am looking for a speaker that will work well in this setup. Currently I am using a ...
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51 views

How to make a very simple mp3 player? [closed]

I'm trying to make a very very simple mp3 player. Here's what I have in mind(please check it and say whether it is possible) : *First I will program a microcontroller to read an mp3 file from a ...
2
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2answers
105 views

Low voltage audio amplifier clips on 8 ohm loads

Exposition time: One could call me a freshman in electronics and I just designed my first little audio amplifier for headphones. (Pocket design, I want to be able to drive 4 headphone pairs from a ...
2
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2answers
92 views

Designing a stiff voltage source using an emitter follower

simulate this circuit – Schematic created using CircuitLab I am new to electronics, and I am trying to do Exercise 2.2, page 67 of The Art of Electronics. Use a follower with base ...
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1answer
59 views

Op-amp and manipulating its linear output range

First of all let me give some background on the problem. I'm not a native English speaker and I have a basic understanding of amplifiers and op-amps. I am having trouble with one problem in English ...
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1answer
31 views

Impediance mismatch and amplifier question

I am converting an aviation headset to take a Bluetooth signal. The headset speakers are \$150\Omega\$, and the Bluetooth adapter I think is \$10\Omega\$. The mic will not be used. Can anybody ...
0
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1answer
35 views

What would be the peak voltage value of two combined signals (one noise and one sinusoidal signal)?

As I learned before, the peak voltage value of two combined sinusoidal signals is the sum of the two amplitudes, for example, \$0.6\sin(ax) + 0.8 \cos(bx)\$ can be \$+1.4\$V or \$-1.4\$V. Would it be ...
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2answers
165 views

How to improve lm386 amplifier circuit

I am new to the world of audio amplifiers however i am quickly trying to learn. I have built a simple circuit using a circuit based on what I read in the database. The circuit works however there is ...
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1answer
51 views

Why is my guitar amplifier acting like a radio when I touch the volume knob?

I just bought an acoustic/electric mandolin (Ibanez M511SE-DVS) that I decided to test out with the only guitar amp that I have (a Baja BG-10). It works fine, but I noticed that when I have my finger ...
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0answers
41 views

NPN Transistor Noninverting Amplifier

I know how to design an inverting amlifier with a NPN transistor. Now I need to make a electret microphone amplifier to connect with Arduino, which only reads positive voltage values. Is there a ...
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1answer
222 views

Why is my instrumentation amplifier's output voltage completely wrong?

I'm trying to amplify the voltage of my load cell (Wheatstone bridge I believe), but my calculated values are not the same as my experimental values. The load cell outputs a differential voltage of ...
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2answers
87 views

Mic Amp Mixer and Audio Distribution, Won't Work! Help! (Update 2) (Solved!)

I'm new to this forum and I really don't know much about Audio Amplifier Circuits. Hope you can help me. Here it goes: So basically what I'm trying to do is a circuit that mix 3 channels, ...
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2answers
94 views

I want to operate a DC 9v relay with a small power

Can a lightbulb be switched on using two mobile phones? (Make a call and the bulb switches on) I need this for a kid's school project so the questions like should the bulb keep glowing after the ...
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3answers
65 views

Effect of non-inverting op amp on the AC and DC components of the input

I was wondering what the effect of an op amp like the one in the image below is for an input signal such as \$0.5\sin(2000\pi t) + 0.5\$ V? Are the DC and AC components amplified with the same gain? ...
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1answer
63 views

Use of Audio Tranformers in Amplification

I came across this ckt to make a wireless ear phones using Infrared Signals from IR LEDs. I am unable to understand the use of Audio Transformer here to amplify the audio signal, instead OpAmps would ...
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2answers
42 views

Step up transformer for low frequency AC with DC offset

What is the best way to step-up a low frequency voltage with a DC offset? I have the following signal coming from a function generator: \begin{equation} V_f(t)=8 Sin(2\pi f t+\phi) + 4 ...
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0answers
42 views

PWM to proportional bipolar control with push-pull amplifier. Need input and opinions

I'm putting together a circuit to control a (small wattage) TEC device in a bipolar manner. The idea is to have a micro controller put out a 3V3 PWM signal, level shift it between +- 3 V and filter it ...
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1answer
84 views

Circuits in audio amplifiers to protect speakers

I hear that there are at least two kinds of circuits in modern audio amplifiers solely for the purpose of protecting the speakers against excessive loads on powering on and off. Particular function ...
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1answer
63 views

From grounding to audio amplifiers

Ultimately I would like to assemble this simple audio amplifier: Given my lack of any significant knowledge in the topic I have several problems and questions. Grounding: In the thread What is ...
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1answer
61 views

DIY wifi radio radio NOISE!

I am building a mono, internet enabled, WiFi radio and I have a problem. I am running into what I believe may be a grounding issue. When I turn the system on, I hear all kinds of noise coming from ...
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2answers
163 views

Microcontroller PWM to bipolar push-pull amplifier issues. (level shifting)

I'm trying to design a circuit that allows a micro controller (arduino) to control a voltage to a load. The load voltage needs to be bipolar in nature (+- 3 to 5 V) for use in controlling a TEC. My ...
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1answer
38 views

Sync filter in a lock-in amplifier

I've got two questions: What does a sync filter in a lock-in amplifier? What are pros and cons of using it?
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1answer
51 views

Audio amplifier not working after changing source (LM386L)

I have this simple amplifier here: I tested it with a regular PC audio jack input. Works fine. The problem is when I try to use it with a telephone (Panasonic KX-DT333, 2.5 mm jack). To be sure ...
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2answers
55 views

Operational amplifier with reverse diode

On the first picture is a simple schematic. For example, we can get the transfer function simply by equaling "ud+u2" and "Ad*(u1-u2)". The transfer function is: u2 = (Ad*u1)/(1+Ad) - ud/(1+Ad) On ...
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1answer
45 views

Difference amplifier show fixed voltage on its output

I'm using a difference amplifier as shown on this page: I double checked my resistors values, I have RA=10k and RB=56k. I'm using a 5V reference and a 0V ground. On the actual board, I have ...
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1answer
79 views

Connecting two power supplies with almost like voltages to an amplifier in parallel

I have recently been working on a custom sound system in my living room. For the subwoofer, I am using a 1000W amplifier. This is currently running off of a 12V computer power supply that outputs ...
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0answers
79 views

Two-stage MOSFET operational amplifier

I've recently done a Lab at the Uni to make a Mosfet 2 stage op-amp shown in the image below: A lot of simulations were done to understand how the op-amp worked, and whether it works correctly. ...
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1answer
89 views

How to desgin a Power Amplifier

I have several electronics books from which I am presently reading the subject of power amplifiers. I noticed two different approaches. In the first book, the author claims that a power amplifier is ...
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1answer
59 views

Class A power amplifier: voltage and current

I am always having problems knowing the difference between providing a load with a voltage and providing the load with power. So we have a Class A common emitter amplifier with a load resistor ...
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0answers
38 views

Need suggestions about a narrow bandpass filter design

I am now designing a narrow bandpass filter. Requirements are shown below: Center frequency is about 2kHz(10% flutuation is OK). The gain of center frequency is about 34dB(the higher the better,up to ...
1
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2answers
58 views

Inverting or Differential Amplifier? (Or neither?)

I have been searching for how to calculate Vout in the following operational amplifier circuit, but so far I have come up empty. I feel it is either an inverting amplifier or a differential ...
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0answers
29 views

Bipolar junction transistor using alternative current amplifier units

Here's the problem: A BJT transconductance amplifier is being convert to a current amplifier And the correct equation for this is: I don't understand how this equation equate to a current ...
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1answer
74 views

Input 5V 100mA, output 200mA

I am new to electronics. I have come across a problem which I face. Will need some advice from here, as I am a student and would like to know: is there any way I can increase current in a circle. ...
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votes
5answers
98 views

Is there any current gain in a FET amplifier?

I have seen many books, but no one gives any information of the current gain parameter in a FET amplifier (low signal analysis). So I was wondering is there any current gain in FET amplifiers or not?
2
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5answers
145 views

Speakers as microphone

I've seen this following post regarding using the speakers as a microphone: http://skeptics.stackexchange.com/questions/5664/can-a-computer-be-hacked-to-use-a-connected-speaker-as-a-microphone There ...
1
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1answer
70 views

Output resistance of Emitter Follower

I have to measure \$R_{in}\$, the input resistance seen by the signal. It was told me, that the quickest way is measuring the voltage gain using oscilloscope, insert a resistor before \$R_B\$, ...
2
votes
1answer
65 views

Difference amplifier schematic

I am trying to get this difference amplifier working, but it doesn't seem to be outputting what I want it to output. $$ V_1 = V_{in}\qquad V_2 = -0.5\mathrm{V}\qquad R_f=R_i, \quad A=1 $$ I want ...
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2answers
213 views

Anti-aliasing filter closer to amp or ADC?

I'm designing a board with several amplified analog signals being fed into the internal ADC of a PIC DSP (dsPIC33FJ256GP710). Because of the board size/shape restraints, the analog buffers can't sit ...
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2answers
79 views

Internal resistance of signal source

It was told me that a signal sent to the circuit can be rapresented by \$V_{sig}\$ and \$R_{sig}\$, where \$R_{sig}\$ is the internal resistance of signal source. Now, let's consider that we have a ...
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1answer
83 views

How to figure out battery life of audio amplifier?

I have a design of an audio amplifier. It has some special features but basically it takes in an audio signal does some filtering, and amplifies it through a class D amplifier chip. The chip says it ...