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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53 views

Input Impedance of amplifier circuit

Why we need to consider the emitter resistance re while calculating input impedance of the given amplifier circuit? Is this a compulsion? I found out that even in case of common collector amplifier ...
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2answers
35 views

CMOS: dual of cascode circuit

If this is a differential cascode CMOS amplifier simulate this circuit – Schematic created using CircuitLab (where the "first" stage is nMOS and the "second" one is pMOS), can the ...
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0answers
53 views

Why deliberately mismatch impedances in RF?

My professor wants me to design a cascaded RF amplifier, with mismatched stages. The reasoning is to increase bandwidth. Is this correct? If so, can anyone elaborate on the theory why mismatching ...
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1answer
74 views

Why don't we use cascoding in RF amplifiers?

I need to design an RF amplifier with high gain. It seems every RF book teaches cascading, but not cascoding. Is there a disadvantage to cascoding? It seems like we don't need to match impedances with ...
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0answers
30 views

ADC input type for audio amplification

I am building a class D amplifier for my car radio. I will be using one of the AVR ATmegs ADC for sampling the input signal. I have few questions regarding the connections between the radio and ...
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1answer
40 views

Is my understanding of how this amplifier circuit works correct?

Hello. This is the amp that I'm trying to wrap my head around. This is how I understand how it works and I'd love your input if what I say makes sense: The input voltage is a sine-wave of ...
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2answers
70 views

what does it mean for a to BJT operating at the edge between the active and saturation modes?

ive recently been fascinated with diodes and was wondering how i'd design a circuit that works at the edge of the breakpoint between the active and saturation mode. How would the circuit be analysed?
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2answers
32 views

BJT Amplifier in AC mode

In the lesson on BJT Amplifiers, we were told the we can find the AC equivalent circuit by replacing all capacitors by short circuits, inductors (if any) by open circuits, dc voltage sources by ground ...
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1answer
39 views

How to calculate gain of wheatstone bridge + differential amplifier?

I have the following circuit: I have a hard time determining the mathematics of this circuit. If we ignore the Wheatstone Bridge to the left, focusing on the differential amplifier, i know that the ...
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1answer
66 views

Why is my mosfet driver circuit clipping lower voltages?

How can I fix this? I've been trying for hours. I want to try and get 0-20V and 2.5A out of 0-5V input (V3). I pretty much chose a random n-channel mosfet that I thought was in spec, but I have a ...
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0answers
33 views

How easy is it to damage my amplifier or speakers? [on hold]

I have never been good in electronics so I would like to hear some opinions from you about a situation where I left my audio system in a room with a bunch of drunk guys and they started using it when ...
2
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4answers
129 views

Differential Amplifier doesn't output the expected voltage?

I have the following differential amplifier in simulation. According to the theory I know, the output should be 0.2V - the difference between the two inputs at 2V and 1.8V. What am I misunderstanding ...
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1answer
78 views

Transistor amplifier circuits

What is the ac collector resistance for the transistor Q1? I am having trouble finding which resistors are in parallel with each other in the circuit above. I want to find the voltage gain and power ...
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1answer
44 views

How to remove degradation in voltage gain when replacing the original \$R_L\$ with a small value resistor?

For the following common-emitter amplifier, the original \$R_L = 4.7\space kΩ\$. When I replace it with a small value resistor (\$100\spaceΩ\$), the voltage gain will drop. Is there any way to drive ...
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1answer
47 views

How to amplify a small AC (no DC offset) wave with an op-amp powered from a 0-5V rail and a pot-varying gain?

I'm having a brain hiccup and can't figure this out. I've tried using simple summing amplifiers where I add my wave to an offset of 2.5V and then High-pass the offset. However, I need to be able to ...
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1answer
38 views

Cascades instrumentation amplifiers with a buffer in between stages: What should I use for buffer?

I have to cascade two instrumentation amplifiers, INA126, and in between the stages I want to use a buffer. How should I make the buffer? The output from the first INA126 is of few volts.
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1answer
44 views

Connecting tone generator to a Sansui b-1000 [closed]

Lets just just start out to say that I don't know the slightest about the wonderful world of electronics. In the Netherlands you're supposed to do a PWS-project in your final year of high-school about ...
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3answers
40 views

Opamp Voltage Doubler Unstable (After Extended Operation)

I've been working on a circuit which would drive an industry standard pneumatic regulator (E/P transducer). The transducer takes a standard 0-10V command signal with a typical input impedance of 6.5 ...
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1answer
29 views

Bridging Discrete (BJT) Amp Channels

For my Electronics II class, I designed a discrete BJT amplifier circuit including a VGain, Buffer, and Power stage. I succeeded in meeting the specs, and the next step is to improve our design in ...
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3answers
61 views

Controlling audio singal with digital potentiometer?

I am very confused about how to go about using my digital potentiometer to control an audio signal. I have a MCP4231 digital pot and would like to use it as a MCU controlled variable resistor for gain ...
2
votes
1answer
58 views

What is Transient Intermodulation Distortion?

I've looked at Op-amp slew rate over frequency How it is possible to make bad audio amp? Which op-amp for audio? as well as several papers about the topic but although I may get the basis of what ...
2
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2answers
106 views

Polarity of feedback for a mosfet circuit

I came across this question in "fundamentals of microelectronics" The objective is to find out the polarity of the feedback. Could someone help me with this? My approach to this question is as ...
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1answer
41 views

How can I debug the amplifier section of tuxgraphic's powersupply?

I've built this circuit: http://www.tuxgraphics.org/common/images2/article379/powersupply.gif Here is a closeup of the amplifier section which I've built: simulate this circuit – ...
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2answers
54 views

BJT In Reverse Avalanche Mode

I want to connect a BJT as a zener diode, that is operating in the avalanche mode when the Base and Emitter is reverse biased. My question is if the data sheet states the forward current for Base and ...
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1answer
58 views

Audio amplifier coupling issue

I keep getting oscillation / uncontrollable noise with the following circuit. My input is a balanced audio signal which goes through a TL082 op amp configured as a differential amp. The output of ...
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2answers
50 views

How can I make a log amplifier's logarithmic region span across the range of 0-5V input instead just working close to 0V?

I need to implement a log amplifier. Currently I'm doing it using a diode in the negative feedback loop but it only really gives me the log response close to the zero input, with the amps output ...
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2answers
109 views

How does a vacuum tube amplifier work?

How does a triode amplifier work? I mean, how does the different components help in amplifying the source wave?
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2answers
57 views

how to compensate power drains in dc circuits?

This has been on my mind for a while. Lets just take any electronics device. Lets say a mobile phone or a laptop. They have fixed voltage and current, but some components needs higher voltage/current ...
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1answer
58 views

Load cell amplifier circuit

I'm designing a circuit to take two load cells as inputs, and make their sum. I'd like to know your opinion about the design. Each cell is connected to one instrumentation amplifier (INA122P). ...
1
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1answer
47 views

home audio: How much current flows through my speaker amplifier's output?

In a recent project I used relays to electronically control a multi-room speaker selector. I wired these relays in parallel with the physical switches in the box. When I was designing it, I wasn't ...
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1answer
82 views

Powering 100W amplifier with 12V rails from ATX power supply

I've got some old speakers that I'm planning to power using this 2x50W amplifier(link)(I'm open to suggestions of a better quality to price amp). To power the amp I was thinking of using an old ATX ...
0
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1answer
49 views

Matching an amplifier to speakers and subwoofer [closed]

I've got a couple of old Bose speakers and bass and I'm looking to wire them with an amplifier so I can use them with a computers sound card. The speakers' manual can be found here. For the speakers: ...
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2answers
59 views

Complex circuit analysis

I need help solving the circuit above. I don't understand how to analyse the op amp using the small signal model in order to calculate the Vout/V3, the input resistance (Rin) and output resistance ...
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2answers
64 views

Amplify speaker with 9v battery and one transistor

I started electronics recently and I'm trying to make the most basic mp3 amplifier. I try to amplify the music from my phone to the speaker. My phone already amplifies the sound when I connect it ...
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0answers
59 views

Operational amplifier with low voltage as input

I would like to measure the current from a circuit. So I decided to use a shunt resistor. In this case I choose to use two 50 mOhm resistors in parallel, so I have 25 mOhm resistance. Because I would ...
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1answer
27 views

Would T feedback network of transimpedance cause serious distortion?

I am now designing a transimpedance using ADA4062-2 to detect signal from a photodiode. The first image is the equivalent circuit. The signal from PD contains 1kHz sine wave and 2kHz sine wave and ...
4
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6answers
279 views

Reradiating antena for GPS

I need to test and maintain a batch of devices which contain GPS modules. I can work on the rest of the device, but when it comes to test the GPS part I have no signal on my desk, no matter how near I ...
0
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1answer
60 views

Should I use a passive or an active filter?

simulate this circuit – Schematic created using CircuitLab I need to design an am receiver as a project. On the front end I have three modules; BPF1 the "roofing filter" or the ...
4
votes
2answers
39 views

Decreasing ADC Reference vs. Amplifying signal

I have a sensor interfaced to ADC but the Range I am getting is not enough, so now there are 2 options, Gain up the signal or Reduce ADC Gain. But as I heard it, reducing ADC gain will cause more ...
1
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1answer
66 views

555 and output amplifer with different Vcc supplies

I want to increase the power of the push-pull amplifier in this circuit. The left 555 generates a square wave and the righthand 555 is triggered by it, and the output of both is amplified by the pairs ...
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0answers
45 views

Do I need an additional quenching resistor?

I'm assembling an Avalanche Photodiode (APD) + Amplifier circuit and I was wondering if I needed an extra resistor between the APD and the amplifier stage. I'm aware that often APD's require quenching ...
0
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1answer
34 views

Help identify ic marked 85616 HSS8444 3

I have a small collection of these as well as a few other unidentified items. DIP-16 pkg. Top markings; 85616 HSS8444 3 Bottom markings; 1720 90W
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0answers
70 views

Can any one give reason for this configuration of oscillator

Please give reason why this is is Common-Base configuration with Base feedback.
0
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1answer
59 views

Non-inverting op-amp output problem

I have built very basic non-inverting op amp circuit and for some reason it outputs just 4V DC line instead of amplified sine wave. It happens only on breadboard, simulation works ok. I'm pretty sure ...
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2answers
71 views

Analog circuit to check if an audio signal is present?

On the project I am working on, I have 3 line-level audio signals, and I need to determine on an arduino if a non-silent signal exists on each line and act appropriately (in my case, "unplugging" a ...
0
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1answer
30 views

Problem in a receiver circuit

I have following circuits : Rf Amplifier : Mixer : The amplifier is able to give me a good gain of around 200 to 300 for signals in 100 MHz range. The mixer, which follows the amplifier, is ...
0
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2answers
99 views

I can not receive radio waves using LM386?

I've made two different circuits to receive RF using LM386 but they doesn't work. I've changed the values of C2 and L1 to change the frequency. I've also changed the gain but nothing happens. The ...
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1answer
63 views

Cascaded Op-amp circuits

Any help would be appreciated.
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2answers
118 views

How to subtract and amplify signals

How do I draw a circuit diagram that subtracts two inputs signals and then amplifies the subtracted signal by a factor of 839?
3
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1answer
183 views

Load cell and amplifier

I'm trying to get a reading from a Digi-Star load cell. I'm using the INA122 instrumentation amplifier, the schematic is attached. Nothing complicated, I connect the cell output directly to the ...