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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0answers
30 views

designig an ampilfier [on hold]

I want to design a differential amplifier with some Specifications below Cmmr>100db , avd>110db, output swing>5v , vcc=6, and vout=0 for vin=0 , RL=500ohm ,and with feedback av=1 could you please ...
1
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3answers
78 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 ...
-3
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0answers
24 views

What is the advantage that Voltage biased has over the current biased BJT Common Emitter Amplifiers? [on hold]

I would like to know the difference b/w the Voltage biased and current biased BJT Common Emitter Amplifier and their advantage sand uses? And can't a transformer be used for biasing? ANd base biasing, ...
-3
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0answers
42 views

Designing of charge amplifier for piezoelectric [on hold]

I am working at Piezoelectric. I use CEDRAT LA75 for amplifier. datasheet of LA75. I want to design charge amplifier like LA75. Values of bandwith range, input output range should be same. I want to ...
1
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7answers
80 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
58 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 ...
-1
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0answers
21 views

What is the function of 'Serial time code message (ToD) (RS-232 serial line)' as provided in a specification of distribution amplifer? [migrated]

What is the function of 'Serial time code message (ToD) (RS-232 serial line)' as provided in a specification of distribution amplifer? http://spectracom.com/products-services/precision-timing/epsilon-...
0
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2answers
60 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
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1answer
95 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
81 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
62 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 ...
0
votes
0answers
28 views

Amplifier for unknown speakers (Bose Soundlink) [closed]

I've speakers from an old SoundLink Mini whose circuits don't work anymore and I was looking to add an amplifier ( and later a bluetooth module) to use these great speakers and case! I've had an hard ...
1
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4answers
356 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
71 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
79 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
73 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
votes
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
53 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
70 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 ...
0
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2answers
54 views

lm358 arranged as a 5 volt Buffer

simulate this circuit – Schematic created using CircuitLab I am trying to connect my lm358 so that it acts like a buffer. I am connecting: VCC to + 5 volts Ground to Ground Non-inverting ...
-1
votes
0answers
114 views

Generating PWM with dither [closed]

I have pwm signal description: Supply voltage: U = 27V Current control: PWM 600 Hz + 37 Hz (dither) Dither amplitude rms value ...
0
votes
1answer
64 views

How to improve gain of class A amplifier

I constructed the following two circuits: Fixed bias amplifier. simulate this circuit – Schematic created using CircuitLab Voltage divider bias circuit. simulate this circuit ...
3
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1answer
42 views

Base resistance in Tee Model

This is about the 'TEE' Model in BJT small signal analysis on CB configuration. During the lectures, the one I learn is this model; But in some books I found a different model with a base ...
0
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1answer
36 views

Matching speaker specifications with bluetooth audio board specifications

As the title states, I am having trouble interpreting the specifications for a Bluetooth audio board I have to determine what kinds of speakers I need, or if I need an amplifier circuit between my ...
0
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1answer
40 views

Can an ordinary transformer be used for coupling the speaker with a transistor amplifier

Audio transformers are not available in my locality. However, I have bought an ordinary transformer. It has the following specifications: Primary voltage: 230 V Secondary voltage: 6 V Current rating: ...
1
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3answers
83 views

Correctly powering amplifier and speakers

I have a few speakers that I salvaged from broken electronics and I plan on buying an amplifier board to drive the speakers. I'm currently looking at an amplifier such as this one and have sketched a ...
0
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1answer
48 views

Finding the short in my receiver (AMP circuit)

I will be glad to get your help to solve the mystery in my MARANTZ-SR4500 receiver.. The problem is that after turning on the AMP I got PROTECT MODE and it turned off. I find out that the source of ...
0
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1answer
38 views

Portable Speaker Powered by Battery and Power Supply Separately but Can Charge the Battery From the Same Power Supply [duplicate]

I'm building a portable speaker using a PAM8403 amp, 3.7v battery, and a battery charging module, all powered by USB input. What I want to do is be able to switch between 1) charging the battery ...
0
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1answer
46 views

Single supply amplification

I have made a single supply non inverting amplifier. The supply voltage given is 5 V. The schematic is shown. Now the problem is I am not able to generate 2.5 V accurately which is affecting ...
1
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0answers
34 views

I need to find the uppers and the lower bound of 3dB frequency

How can i find the upper and lower bound of 3dB frequency ?? I think I have to make first a small signal analysis including the capacitors Cgs,Cgd ..
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2answers
63 views

Skype Phone Project - Help with Audio Amplifiers Selection

I am doing a project that involves using a landline phone to work as the speaker and microphone for Skype calls. A representation of the final design is given below. I have a landline phone in ...
0
votes
3answers
106 views

Best way to amplify the photoresistor signal

I have the following schematic. simulate this circuit – Schematic created using CircuitLab And it graphs to an almost stratight line. It is supposed to be a heartbeat sensor. From what I ...
0
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0answers
40 views

Remove mains hum out of amplifier

I have a headphone amplifier that is afflicted by mains hum 60 Hz and upper harmonics, below is an FFT of the spectrum with nothing connected to its inputs. In headphones you can clearly hear a buzz-...
0
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1answer
69 views

INA155 reference pin not working

To test the INA 155 I gave a sine wave of amplitude 0.2 V p-p 100Hz. It was operated at 5 V single supply. The reference pin was connected to 2.5 V from an op amp buffer. There seems to be no offset ...
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2answers
77 views

Single double triode vacuum tube for headphone amp at high voltages

I'm planning to build a single double triode vacuum tube as I have seen many schematics even though most of them are low voltage (20-40v). However I didn't seem to find a high voltage single double ...
5
votes
2answers
122 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 /...
2
votes
2answers
67 views

Calculating the Gain in an Amplifier circuit

Having some issues calculating the gain in circuit below, it is apparently 1802, but I can't seem to arrive at this answer. If anyone could help explain how to get this answer I'd be very appreciative!...
0
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2answers
66 views

Unexpected results when trying to amplify voltage across a wheatstone bridge

I am working on a project, and am trying to amplify the voltage across wheatstone bridge. Here is the diagram: where \$R_1 = 1,000 \Omega\$ \$R_3 = 10,000 \Omega\$ and \$R_2\$ is a potentiometer,...
0
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0answers
36 views

SOS! Finding Open loop gain - breaking feedback loop

I’ve just become quite confused regarding on how to break the loop; please can you clarify if there may have been a mistake in one of the solutions to part d) of this question where it it is required ...
0
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1answer
40 views

Calculation of Breakdown Voltage

How can we calculate the breakdown voltage of a BJT in ADS? Is it Possible or not in ADS? Problem:- I have a ADS BJT model. I am using that to generate high voltage output. For that i need to bias ...
4
votes
1answer
320 views

Identifying this "IC”, Trying to reverse engineer a board

Part 1: the board and how it's connected I'm looking at a headphone sound amplifier that is used to help experts detect pests in palm trees when a microphone is placed on the trunk of the palm tree. ...
0
votes
2answers
77 views

what is the maximum output voltage from an opamp in general case?

In general, what is the output voltage that an amplifier (not rail-to-rail output type) can provide,if it is supplied for example Vdd=+24V and Vee=-24V which is the maximum value I can get "for sure" ...
1
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3answers
62 views

How to remove noise from power adapter

I am making an audio amplifier using an LM2879. I am using the schematic provided in the data sheet. For a starting point, this design works pretty well, although the base cutoff point could be a ...
0
votes
1answer
28 views

Calculate the parallel value of resistors at base of common emitter amplifier

I don't know if questions can be asked like this here but if they can I want this question. In an exam paper I saw a question to determine the parallel value of the R1 and R2 resistors in the image ...
0
votes
3answers
61 views

Gain vs Output Impedence

I am currently trying to improve my understanding of analogue IC design and my textbook kind of brushes over this problem. It is made quite clear that a low output impedance is desired so that the ...
1
vote
1answer
71 views

How many stages of transistor amplifiers should be used in order to produce an audible output

I have constructed this amplifier as shown in the circuit diagram: simulate this circuit – Schematic created using CircuitLab I have made a few inferences: Reducing the value of ...