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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5 views

hemt phemt transistor - need manual/book

I have to design a microwave amplifier in the frequency range of 0-15GH. To this end, I need to be able to design circuits with HEMT/PHEMT transistors. Is there a comprehensible manual that teaches ...
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1answer
42 views

7w IC amplifier

[![enter image description here][1]][1]I have a 7W IC amplifier in its instruction it says connect DC voltage to 12-16 DC. Connect audio source to "IN" and "G". Connect 7W speaker to "SPK". In lab I ...
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1answer
47 views

2.4GHz signal through 900MHz amplifier?

Nobbie question, but I was wondering: if I were to generate 2400MHz signal in VCO and put it through, let's say 900MHz RF amplifier, will the output signal be 900MHz? Or would this experiment fry the ...
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1answer
50 views

40kHz signal amplifier with ua741

I am trying make an amplifier with UA741 to amplify signal from ultrasonic sensor. I tested this circuit with a sinusoidal signal from function generator but this only raised the signal level adding ...
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2answers
96 views

Is the current gain value constant for a single BJT ?

hfe of a npn bjt transistor is given by collector current / base current so to calculate hfe you need to know the collector current and base current (which can be set using resistors) . I have to ask ...
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1answer
50 views

Actively biased JFET Amplifier

simulate this circuit – Schematic created using CircuitLab Its just the basic diagram (the actual circuit is a low noise amplifier at 5.5GHz).It does work very correctly.In this circuit ...
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1answer
39 views

pseudo differential input of amplifier

The Signal Recovery Model 5184 is an ultra low noise preamplifier. The product description says ... and incorporates a special pseudodifferential input stage that can be floated to give the ...
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1answer
49 views

Question about output current

I've got huge three-phase transformer, primaries are connected in Y configuration, secondaries in Delta, then goes to 6 diode bridge rectifier. Output is about 200 amp 52 VDC. In short, how many ohm ...
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3answers
135 views

How exactly does a transistor amplify the input current in CE configuration

I have gone through tons of forum discussions and videos and books but they all explain in terms of mathematical equations that factor the input by a 'larger than 1' number. What happens physically ...
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2answers
36 views

Hi-Fi Stereo Amplifier gain regulation with potentiometer

This is my first question ever so please don't kill me :) I have built a stereo hi-fi (end) amplifier 2x10W based on a IC TDA2009. I have bought it as a construction (learning) kit ready to solder. ...
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1answer
41 views

Repairing/understanding this guitar amp master stage

The failure For the past few months I've been looking to repair my old-style Roland Cube 60 watt amp after it had been left out on a cold night. The point at which it failed was when I turned it on ...
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0answers
15 views

Measuring gains on 2 channel amplifier

Let's say I had an input stereo signal and two black boxes that were each going to amplify a channel on a stereo speaker signal. Given that part of the two signals are similar but they are not the ...
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1answer
59 views

Electret microphone into iMac 3.5mm TRRS headphone jack amplification

I have this electret microphone: http://www.farnell.com/datasheets/1505849.pdf And I've put it onto a 3.5mm TRRS (4 pole) jack to go into the iMac headphone jack. For the iMac to recognise/accept the ...
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1answer
48 views

Microwave amplifier characteristics - don't undertand [closed]

Please, look at http://www.rfcomp.com/hd24223.aspx (the spec file is downloadable in this page). This is a microwave amplifier, and I have several questions. 1) What is "noise figure" ? 2) What ...
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1answer
74 views

Can I connect multiple speaker boxes to a single amplifier output? [closed]

I've seen arrays of passive speaker boxes (high output passive professional PA speakers) that were connected to each other and only the last (or first) one was connected to the power amplifier (a very ...
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1answer
61 views

Can I run my audio mixer off the battery powering my amplifier?

Background info: I have a small battery powered 25W amplifier/speaker combo. KustomSound CB25X, with two 6V 4.5Ah SLA batteries wired in series for 12V. Fully charged, the voltage seems to be close ...
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1answer
34 views

2x50w stereo vs 100w mono amplifier efficiency

Which is better for efficiency. mono 100w amplifier or stereo 2x50w It is important because I'am building a portable speaker and it is really important for me to use little power. Also which ...
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2answers
34 views

Picking battery for power amplifier

I have bunch of TDA2003 (class AB) amp ICs and I would like to make some amplifiers with them. One would be stationary bridged 20w version and one portable version. However I'am a beginner and I never ...
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1answer
51 views

Portable headphone amplifier - max output and power supply [closed]

According to the specs listed on this page, that portable headphone amp can produce different maximum voltage, depending on the impedance of headphones: Max Output @ 600Ω 4.146 VRMS Max ...
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1answer
45 views

Power Amplifier Bypass Switch Convention?

I have an RF power amplifier (PA) for a transceiver module I'm designing. My transceiver is capable of outputting +14 dBm at the 915 MHz ISM band and the RF PA will be used to further amplify the ...
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2answers
45 views

Tube amp low voltage [duplicate]

I am building a 18W tube amplifier based on this layout. I found a schematic for a similar amp. my problem is that there is low plate voltage on all of the tubes (by plate I mean pin 3): when I ...
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1answer
48 views

tube amp power transformer

I am trying to build a 18w amplifier based on this schematic however my power transformer doesn't have a center tap on the secondary winding Is it possible to use this power transformer for this ...
2
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2answers
261 views

Is there an audio amplifier chip or circuit that amplifies certain amplitudes in a signal less or more than other amplitudes?

Like for instance, that would amplify on an exponential curve where the lower amplitudes get the maximum amplification and the highest amplitudes would get no amplification? Is there an analog chip ...
3
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1answer
76 views

Problem with a class AB amp

I have a simple preamp circuit coupled with a class AB power amp. The design is quite simple and I am pretty sure I already made it work a couple of years ago. simulate this circuit – ...
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3answers
57 views

Single MOSFET Amplifiers

Why is it that when I see single MOSFET amplifiers or even complementary ones (one NMOS and PMOS), they would use what in single BJT amplifiers would be called "Common Emitter Amplifier". The output ...
2
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1answer
45 views

How Much Current Draw From Speakers/Amplifier?

So I plan on using the VS1053 Codec connected to a class D Amp (2 x 2.8W channel) with two 3W 4 Ohm speakers. If I supply 5V to this setup, what would the current draw be at full use? Codec: ...
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4answers
190 views

Is it voltage or power of the signal amplified when the opamp amplification is given in dB unit?

Today, one of my colleague said that he entered a preliminary examination in a company after his job application. One of the questions is exactly "Design a non-inverting amplifier with 20dB gain.". ...
2
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1answer
35 views

AoE3: Grounded Emitter Amplifier Distortion

I'm trying to understand a passage in the 3rd edition of Art of Electronics which explains the distortion of grounded emitter, common collector amplifiers vs. those using an emitter resistor (ch. 2, ...
6
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3answers
139 views

60Hz “click” or clipping noise when differential amplifier is surrounded by salt water

I am a graduate student attempting to take electrophysiology recordings from a lobster under water. In the current set up I am using, two differential amplifier boards are attached the the lobster's ...
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0answers
99 views

Operational Amplifier frequency problem

I am using an operational amplifier in an inverting configuration with a gain of 10. (-R2/R1= 10), with a high cut-off frequency of almost 30 Mhz. However, while testing whenever I apply an input ...
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1answer
73 views

What is wrong with my guitar amp?

I found this 1W guitar amp design on the Internet: http://www.diale.org/punch.html And I am trying to build it on the protoboard. I could not find the IC TDA7052, instead I've got the a TDA7052B. ...
1
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1answer
103 views

How to amplify a very small signal

I am trying to wrap my mind around very small signals; what they mean, and how to amplify them. For example, here is a screenshot from my cell phone. Notice the signal level received is -97dBm. ...
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1answer
40 views

ttl 3.3v but almost 0 amps, max232 does not send anything at 12v

Here I have basic board which has ttl serial working on 3.3v (yes I measured it) but it does not have any amps, it barely can light up pore led diode, with my meter it shows 0 micro amps current with ...
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1answer
53 views

Common-Drain Amplifer vs OP-Amp for unity gain (voltage Follower)

What is the difference between using a nFET vs OP-Amp as a unity gain amplifier, i.e. voltage follower. Application: Provide constant voltage with a variable load, see example below: Min Current ...
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1answer
42 views

input of class E amp

i don't want to lose time on understanding it's theory, i just wanna know what kind of input does it take in, does it take a PWM input like the class D (the one below) ? or just a ON/OFF signal ...
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1answer
43 views

Wireless amplifier antenna

There is something like an antenna that works like an amplifier, repeating every signal in the device frequency operation range but wireless. I mean that this "dumb" active antenna receive every ...
0
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1answer
48 views

Problem Measuring Current in a High Voltage circuit with arduino

I 'm measuring a current in a resistor as shown in the picture below. There I'm using a voltage substractor with an LM324 Operational Amplifier. I'm having trouble in the real World when the voltage ...
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2answers
90 views

Need simple audio amplifier

I'm more of a programmer then a circuit designer (read: I'm not good with EE stuffs at all) but I'm working on an arduino project and it's not loud enough. I was trying to drive a piezo buzzer to make ...
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0answers
47 views

Gain in common source amplifier

Let us consider the Common Source amplifier depicted below: We know that the gain \$A_v\$ of a such circuit is given by \$A_v=-g_mR_D\$, where \$g_m\$ is the transconductance of the MOSFET. We also ...
2
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0answers
65 views

60 dB gain at 20 MHz

I am designing an IF amplifier circuit that needs roughly 60 dB of gain at 20 MHz. I was considering a cascade of 3 x 20 dB MMIC gain blocks but I am wondering if there is a better way? The ...
0
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1answer
45 views

Differences between preamplifier, instrumentation amplifier and LNA

I am confused about the definitions of these amplifiers. It seems LNA is used for RF frequency band but I also see people using INA's for receiver. Why LNA's need careful impedance matching but INAs ...
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2answers
56 views

Why do we short the input when calculating the output impedance?

I believe the title says everything about the question. My issue has to to do with the following: Consider a two-port given by: $$V_1 = Z_{11}I_1 + Z_{12}I_2$$ $$V_2 = Z_{21}I_1 + Z_{22}I_2$$ Cleary ...
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1answer
37 views

Stereo volume control in headphone amplifier

I have a headphone amplifier schematic and I want to make it in stereo. My questions are: Is there any way to realize the volume control with one potentiometer, or should I use some kind of dual ...
1
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1answer
39 views

Does a BJT Class A Amplifier act in Reverse Mode?

The signal above has negative voltage, so should I take it that it is positively clamped or biased? Or, does the NPN go in Reverse Mode, which I don't think it does (as Reverse Mode only explains ...
6
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1answer
522 views

How does this BJT transistor circuit works?

I just wanted to know a little more about this circuit about how it works a more in depth analysis I mean. I know there's some kind of differential amplifier and a Zener diode for voltage regulation ...
0
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0answers
32 views

Amplifier chip overheats without input; how do I determine whether the problem is internal or external?

I'm building a boombox around a Lepai LP-808 amplifier, which seems to be a thin wrapper around the Sanyo LA4636 chip (with some treble and bass adjustment added). The chip has begun overheating ...
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1answer
119 views

Problem understanding the operations of capacitor

So far I've learnt about some different types of capacitor arrangements , such as coupling , decoupling , bypass , filtering , and smoothing capacitor. Decoupling and bypass capacitors are the same ...
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1answer
104 views

How do I amplify an input signal to match the peak of another signal

I would like to build building a Voltage Controlled Oscillator (VCO) for audio applications beginning with a relaxation oscillator build from op amps. Adding a potentiometer to the feedback loop ...
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1answer
56 views

Power supply issue with LM384 audio amp

I made an audio amp using the LM384 : My soldering skills aren't great but eventually the circuit itself doesn't look too bad. To power it, I used an old laptop power supply (18.5VDC - the datasheet ...
4
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2answers
137 views

Amplifying a high frequency signal of 30 Mhz or above using OpAmps

I am testing a 34 Mhz amplifier in an inverting configuration with a gain of 20. The cutt-off freqeuncy of amplification stops almost at 15 Mhz , which is very low. I want it to continue up to 27 ...