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)

learn more… | top users | synonyms (2)

-2
votes
2answers
56 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 ...
1
vote
0answers
39 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. ...
0
votes
0answers
59 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 ...
0
votes
1answer
47 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 ...
1
vote
0answers
32 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
vote
2answers
48 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 ...
0
votes
0answers
22 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 ...
-1
votes
1answer
68 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. ...
0
votes
5answers
87 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
votes
5answers
130 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
vote
1answer
64 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
64 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 ...
1
vote
2answers
198 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 ...
0
votes
2answers
72 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 ...
-1
votes
0answers
98 views

Would anyone explain this circuit? [duplicate]

I know that the transistor works as an amplifier but I can not understand why it is connected this way. I'm a beginner in electronics and I just want an explanation for this circuit (especially the ...
0
votes
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 ...
0
votes
1answer
85 views

Safest way to make a high-voltage switch

First of all, I've dabbled in electronics on and off over the years. I have no formal training. I'm designing a vacuum tube guitar amplifier (seems like everyone is these days). I want to add a ...
0
votes
1answer
82 views

Two-stage amplifier

This is my first time designing a circuit by myself :) The input of this circuit is the output jack of my MP3 Player. The output of this circuit is 4-Ohm loud speaker (sometimes I connect 8-Ohm ...
0
votes
0answers
12 views

Impedance Matching for Amplifier Output [duplicate]

0 down vote favorite I needed some basic advice about impedance matching. I have an RF amplifier with 50 ohm output impedance, capable of generating 400W output power at 500kHz. I am trying to ...
0
votes
4answers
123 views

Impedance matching for amplifier output

I needed some basic advice about impedance matching. I have an RF amplifier with 50 ohm output impedance, capable of generating 400W output power at 500kHz. I am trying to deliver this to a 12 ohm ...
1
vote
2answers
78 views

How to choose a transistor for amplification

I've been trying to find information on choosing an NPN transistor but everything I've found seems to apply to saturated transistors only. I'm basically trying to amplify the current given from a 3mm ...
-1
votes
3answers
56 views

Question about common emitter configuration?

The configuration of the common emitter amplifier is one resistor at the emitter, on resistor at the collector, two bias resistors at the base as shown in this picture : I saw this new ...
0
votes
1answer
41 views

Which output and input to be used?

I'm planning to generate a signal and amplify it. I couldn't find the manuals but I have the detailed pics. The function generator: And the amplifier is here My question is: 1) The function ...
1
vote
1answer
107 views

Would you help me understand this simple circuit?

I have three questions: Is it common emitter or common collector (emitter follower) or something else? How do you recognize it? What is the function/usage of R1 and C1? Are they for biasing the ...
1
vote
3answers
67 views

Does it matter the order of amplification and rms squaring?

If in a circuit a signal is first amplified and then its rms value is found, would we get the same result if first the signal is rms found and then amplified?
0
votes
2answers
97 views

How can I Improve the quality of an amplifier?

I amplify using LM358 Op-amp and 2 resistors. I played a song on my mobile. The output of the Mobile is the input of my circuit. The output of my circuit is connected to 8 ohm speaker. I hear ...
2
votes
2answers
64 views

Input voltage for LM4862 audio amplifier

I just started working on an embedded side project that requires me to pump .wav files through headphones. My main microcontroller is a PIC32, and my audio amplifier is an LM4862. For the DAC ...
0
votes
1answer
56 views

BJT Topologies - Design Principles at RF

Here are some rules of thumb I've learned when designing single-transistor BJT amplifiers: High input impedance is good Low output impedance is good Biasing resistors should draw ~10% of the ...
0
votes
1answer
51 views

Powering a load with specified maximum current of 300mA. Is it safe to use a matching voltage power supply with a higher current rating? [duplicate]

I just bought a guitar amp that can be powered by a 9v battery or a 9v power supply. The instructions that came with the amp specify that the power supply should deliver 300mA maximum. As far as I ...
-2
votes
2answers
152 views

how to choose resistors' value for common emitter amplifier? [closed]

I want to choose the best values of R1 , R2 , R3 and R4 to get the maximum gain (high performance). I design the circuits practically, so I don't need to do a lot of calculations. I want the ...
1
vote
1answer
41 views

Class D inductor current calculation

How do I calculate the required inductor current (RMS, saturation) for a class D amplifier? Assuming the following configuration: Speaker impedance (Z) = 4 ohms Power output (P) = 400W ...
1
vote
3answers
154 views

Control voltage using transistor

I know nothing about transistors except they can be used as simple amplifiers. I do not know which one to use for my project. A port from arduino would give me volts ranging 0V-5V. I have an external ...
1
vote
1answer
43 views

Questions about the front end design of amplifier circuit

Question 1: Recently, i'm working on a design which needs to design an INA front end. The most used circuit like this (please omit the component values): You see, the two 10M resistors which ...
1
vote
2answers
53 views

Class D amplifier output filter calculation

I want to build a simple amplifier with TI's TPA3116D2, which is "filterless" Class-D amplifier. This device can be run with a traditional LC filter at the output, or, if the speaker wires are short, ...
0
votes
1answer
29 views

Convert A weighted voltage output into sound pressure

I have designed an A weighting network circuit. but i cant understand how to convert it's voltage output in to corresponding sound pressure level in dB. So How can I convert these voltage readings ...
2
votes
1answer
68 views

Can PGA be cascaded to amplify small signal?

I need amplify small 50Hz AC signal. The range is from sub mV to hunderds of mV. Can I use multiple cascaded PGAs? Something like: signal_source => PGA205 => PGA204 => PGA204....,
1
vote
1answer
75 views

What does the feedback capacitor do in Right-Leg-Driver?

It so happens I have seen some people mention about connect a feedback capacitor across the opamp for RLD would improve something better. Can someone capable to explain about the use of the ...
0
votes
1answer
66 views

Amplifier stopped working completely after changing op-amp

After replacing op-amp given in the picture with LM386L the amplifier pretty much stopped working entirely. There is only a faint sound on the output - as if the gain was way below 1. Given the ...
-1
votes
1answer
107 views

What kind of amplifier to use?

I'm driving an LED from the output of an optocoupler. Example, I'm trying to find surface errors on a sheet. When the sheet is flat the average output voltage is around 2.45V (based on the circuitry I ...
0
votes
1answer
101 views

How to amplify the signal of a TCRT5000 phototransistor

I'm trying to read the IR signal from my Itron C1S Power meter. It has an emitter that lights up for 10 ms every Wh of consumption. This question is based on my prior question: Use a photoresistor ...
1
vote
1answer
64 views

What is the current gain of this op-amp circuit?

I just happened to see this circuit in some lecture slides and I thought I could solve it. Unfortunately, I've been trying to check my result with an ideal simulation in LTspice and all my attempts ...
0
votes
1answer
62 views

Help me figure out this 12AX7 Tube Preamp mess

A few years ago I built a Tube guitar amp / pedal / preamp with a 12ax7 tube (and some other pin compatible tubes). I don't remember what schematic I used to make it and I wasn't skilled with ...
0
votes
1answer
59 views

Load cell without In-amp

I have a 0-1kg load cell with 4 wires: Excitation + and -, and Signal + and -. I haven't had any problems wiring them up correctly without amplification, and my voltmeter shows me a 1 mV difference ...
0
votes
1answer
54 views

FM Transmitter Amplifier — Maximum output power with non-customized parts?

I would like to build an FM transmitter on my own and I found a nice circuit that acts as a USB sound card to transmit low power FM signals. http://tipok.org.ua/node/35 My plan is to add another ...
6
votes
2answers
261 views

Common Emitter not amplifying

I am trying to make a 27 MHz carrier wave transmitter from a crystal oscillator and a secondary amplifier. Thi is the complete circuit: simulate this circuit – Schematic created using ...
1
vote
3answers
58 views

Would having no power supply but a large input signal damage the amplifier?

I am now learning about the power sequence of the circuit. And wonder that as every amplifier has its own limited input voltage (for example: ADA4004's input limit is V− < VIN < V+), would the ...
1
vote
3answers
118 views

Output impedance refers to open circuit o/p impedance or short circuit o/p impedance?

When we specify output impedance of a two port network, does it imply open circuit output impedance or short circuit output impedance? Wikipedia: output impedance ; Wikipedia: two-port network g22 ...
1
vote
2answers
98 views

Using a DC voltage as the base for a transistor to amplify AC Voltage

I'm a little new to electronics, particularly transistors, so I don't know a lot of the different types and inner-workings of them. I have a diagram which, hopefully, will gradually increase the ...
0
votes
1answer
33 views

Input to amplifier with LPF not working

I am trying to build a pink noise machine to use at work. See schematic below. If I connect the output from the MM5837N (noise generator), directly to the amp circuit. It works fine, and is nice ...
0
votes
1answer
44 views

Problems with OpAmp based amplifier simulation

I'm trying to simulate a simple amplifier for an electret microphone, but having problems regarding the output level and virtual ground. The circuit in Multisim is as follows: What I'm having ...