Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [amplifier]

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)

0
votes
1answer
67 views

Class A amplifier with preamp design

I am currently working on a class A audio amplifier designed to work with line in voltage (about -400mv to +400mv). I plan on using an IRFP240 for the mosfet but am undecided on the transistor stage. ...
0
votes
1answer
148 views

RF Power Amplifier Design

I would like to design a RF power amplifier for an output power of 10 Watts. Since I would like to have a good efficiency, my amplifier should operate in the class F mode (or class E, whatever is ...
1
vote
0answers
90 views

What will be small signal trans resistance gain of shown circuit?

Take beta = 99. I analysed this circuit using first considering this circuit as feedback circuit with shunt-shunt type of feedback and then did the same analysis considering that the circuit is a ...
1
vote
3answers
94 views

why is transformer not considered as an amplifier?

I know that in a transformer the power is conserved on both sides, and hence there's no power amplification as such. That's fine! But if I instead want only a voltage amplification, then choosing ...
0
votes
0answers
40 views

IC for audio amplification of 3W and 4Ohms 2 speakers with Raspberry Pi

I was using a PAM8403 amplifier with Raspberry Pi to run 3W 4Ohms 2 speakers but the sound is low. So I am thinking of building an amplifier circuit. Sound low means when I connected this to mobile ...
0
votes
1answer
33 views

Direct coupling Biasing of Two stage amp

General question. I see a lot of two stage amplifiers with a diff pair input and a cs second stage. In IC design these two stages are always directly coupled ie. the dc bias of the second stage is fed ...
0
votes
0answers
40 views

Passive PA resistor came loose

I need some help! I have an Australian Audio XRS12 speaker. After a gig I heard something rattling around inside the cabinet. I opened it up to find an 8 ohm resistor that had come loose. It looks ...
1
vote
1answer
50 views

Laser audio transmitter - need substitutes

I'm building a laser audio transmitter that uses amplitude modulation to transmit audio via a 5mW laser beam. The transmitter uses a microphone, an operational amplifier (to modulate the signal if I'...
0
votes
1answer
44 views

input resistance of differential amplifier

i have a question about the differential amplifier i know that the input resistance for the common mode is Rin = rpi + 2 Beta Ree / 2 but my question is what is the input resistance for the ...
1
vote
2answers
170 views

Why does it take over 4 seconds to eliminate audio popping in this circuit?

I made a simple audio mixer circuit with its output going to headphones. Right now I'm only testing with a single audio signal at the input, which is music from a smartphone. I hear a pop sound after ...
3
votes
2answers
100 views

Question about differential amplifier

why is there 0.7V instead of 1.2V on the common emitter? if you go through Q1 mesh : Ve = 0.5+Vbe = 1.2 instead of Ve = 0+Vbe = 0.7 from Q2.
0
votes
1answer
86 views

Triphase servo motors and amplifiers from different manufacturers: can they work together?

I'm a newbie here and more generally in electronics. I'm offered used industrial equipment's that would theoretically be of great use for several projects we have in our workshop. More specifically, ...
0
votes
1answer
137 views

Amplifier Settling Time and ADC Resolution

Like the circuit in the figure below, i have an Amplifier that is driving an ADC with 10 bits (3.3v Ref). Its sampling frequency is 10kHz and the signal is a sine wave with a frequency 1kHz and 1Vp. ...
0
votes
1answer
92 views

Class D Amp headphones grounding circuit

I am having a problem with some of the class d amps I've played with (PAM8302A), and it seems like this article here describes my problem: https://www.edn.com/design/analog/4313726/Add-headphones-to-...
-2
votes
0answers
33 views

Op-Amp comparator or amplifier? capacitor in non inverting input

If someone can clarify to me what is the action of this OP amp, is it comparator or amplifier? I know when there is negative feedback the op-amp is an amplifier, but here has a capacitor, what is it ...
1
vote
1answer
82 views

5V digital output to 24V

I'm sure it is a simple solution but I am new to this so please take it easy. I need to come up with something to convert a 5V digital output signal from a USB-1608G DAQ device with DIO to 24V ...
1
vote
1answer
135 views

Tweeter speaker crack on turn on/off when ultrasonic signal is played

I wired a Fostex FT17H to a YAMAHA R-S202D receiver and put a 1µF capacitor on the + line (like the manual suggests). If i play now a "normal" audio file (<20kHz) everything is great but when I ...
3
votes
4answers
436 views

Class A Amplifier Design: Emitter Resistance Voltage Drop

I am trying to understand the design principles of Class A amplifiers, primarily for audio purposes. I have read several times that "the voltage drop across the emitter resistor should be in the ...
2
votes
1answer
29 views

Designing 2-stage BJT CE class-A voltage pre-amplifier with specified goals and without global NFB

BJT CE Class-A Voltage Pre-Amplifier Suppose a design requirement limits the selection choices to the following class-A BJT common emitter stage topologies. No global NFB is permitted. Only local NFB ...
2
votes
3answers
52 views

Class A amplifier - Transistor Q-Point calculation

Reference: http://www.learningaboutelectronics.com/Articles/How-to-find-the-q-point-of-a-transistor-circuit I am trying to understand this q-point calculation. I recently asked a question about the ...
0
votes
2answers
35 views

Load Cell Amplifier

I'm not from an electrical background and looking for possible options to amplify the load cell output. I'm using the following loadcell with a 2 mV/V output. http://www.sentranllc.com/pub/...
4
votes
3answers
4k views

Speaker level to line level

I want to reduce my amplifier output to line-level. I found this tutorial, Connecting speaker signals to line level inputs, which is compatible with 50 W output power. There is also mentioned ...
0
votes
0answers
27 views

ESP32 with LNA and PA

I would like to add a low noise amplifier and a power amplifier to the ESP32. As you may know there is only one RF output on the chip. I was thinking of adding an RF switch, and switching between ...
0
votes
1answer
26 views

A passive differential to single-ended load match

I'd like some suggestions for some passive differential to single-ended speaker audio level matching circuits for a particular situation where an external power source for an amplifier is not ...
0
votes
2answers
638 views

Amp troubles - noisy TEA2025

Recently I got my hands on a small amplifier board containing two TEA2025 ICs. Not sure what had it been used in previously, but the sound was acceptable, at least when removing some resistors that ...
1
vote
1answer
189 views

Controlling a Piston Variable Pump with a Raspberry Pi

I'm involved in a team that is controlling an AA10VG axial piston variable pump using a Raspberry Pi 3 Model B V1.2. I've been delegated to design the circuit which will control the pump's ...
5
votes
2answers
2k views

Rail-to-rail op-amp only reaches 90% of VCC, works sometimes, not everytime

I have created a simple data acquisition module for measuring 5V signals. There are 18 analog inputs on this board, all of which are a copy of the schematic below. Each input has an op-amp (MCP604) ...
1
vote
1answer
53 views

The proper way of using gm/Id plot for designing an amplifier or OTA

For any design of an amplifier or OTA, we are given the specs which we need to achieve including: Gain UGBW or 3db BW Slew rate Power consumption Phase Margin Load capacitance I would like to ...
0
votes
1answer
149 views

How to limit current consumption for integrated class D amp?

I have a small amplifier IC, rated at about 2.5 - 3W output going into a 3W rated 8 Ohm speaker. The input signal is going through a pot. and than into the amp though a cap and resistor in series, as ...
2
votes
2answers
499 views

Why is the output signal of my amplifier heavily distorted?

I checked the circuit 1 million times. I got it from a website. Everything is correctly connected. The sound is loud, but it is very distorted. I use a 9 V battery. Where is the problem? :( ...
0
votes
1answer
98 views

Common emitter amplifier with load resistance

I can't seem to grasp how to calculate the values for a common emitter with a load resistance, to cascade an amplifier in multiple stages. I'm trying to obtain an 8.5-9Vptp output from a 12V supply ...
0
votes
1answer
59 views

Why polarize a differential pair with a diode-connected BJT?

I was having a look at the LM148-family design At the input stage, why would you polarize a differential pair with a diode-connected BJT? If I'm not mistaken, the output resistance is also going to ...
2
votes
0answers
51 views

TDA7294 blew up [closed]

I have created this schematic connection of TDA7294 on and had a PCB solution. Connected to power supply +-25VDC. But at first start the TDA7294 blew up without any load on output pin. I started check ...
2
votes
2answers
113 views

Operational Amplifier Problem

I'm trying to find $$\frac{V2}{V1}$$ as a function of x. I found this circuit but noone gave good explanation. I think I understand the way this potentiometer works, but I just can't work out the ...
0
votes
2answers
138 views

Low Noise Amplifier and Input/Output Phase

I've been designing LNAs for a brief time and I was wondering why the input and output phases is usually never cared for or measured when measuring the specs of the LNA. For example, the only specs we ...
0
votes
2answers
621 views

Amplifier gain too HIGH?

I have this circuit : Two common base amplifiers for amplifying frequency in FM range (88 to 108 Mhz). The Problem is, as seen in the figure, I am getting an output of 1.5 V for an input of 10 uV. ...
0
votes
1answer
147 views

Active Filter and Sine to Square Conversion Issues

Background: I am currently using a SparkFun Electret Microphone and am needing to both filter and amplify the signal before turning it into a square wave to be interpreted by a FPGA. The mic itself ...
0
votes
2answers
157 views

QUCS Darlington pair

I'm modeling a Darlington pair in QUCS to understand better how to use it in practice. The model is below: The DC analysis predicts a current in the base of T1 of about 1uA and a collector current on ...
3
votes
3answers
208 views

Why is KCL giving me the wrong solution?

I'm trying to derive the gain of the following common base amplifier circuit: To do this, I drew the equivalent T-model circuit: . The problem I have is that I get two different transfer functions ...
0
votes
0answers
46 views

EC Sensor (Analysing the Circuit)

I'm doing an electrical conductivity sensor; my goal is to build a water monitoring device. After analysis I decided to build my own circuit and make some improvements to other designs. An EC sensor ...
2
votes
4answers
148 views

Can anyone identify the components circled in black? Weber 6049A Schematic

I have a 1936 era Weber amplifier (6049A.) Can anyone help me identify the 2 components I have circled in black? Red/Purple and Orange/Black (one of the other components also has a green circle on ...
1
vote
1answer
156 views

What is sense terminal/pin in differential amplifiers?

I sometimes encounter a connection terminal called AISENSE in some data acquisition boards. I also see a pin called SENSE in diff. and Instrumentation amplifiers. An example(look at the pin called ...
0
votes
1answer
240 views

Transistors as switch and amplifier to control LED strip

I am controlling an LED strip based on audio input from my phone. I am having some good results, but not exactly what I want, and my ignorance of transistors is holding me back. (I'm a mechanial ...
2
votes
0answers
63 views

Calculating the gain of a specific transistor amplifier circuit

NOTE: There is an error in the drawing above — C1 should be connected to the emitter, not the collector. Hi Electronics SE, hope this is the right place to ask this, if not I'll gladly take it ...
-1
votes
1answer
144 views

NMOS common source amplifier with source resistance

I want to ask Is Vds is equal to Vd ? and What could be the conditions for Vds= Vgs. And what is difference between Vgs and vgs?
0
votes
2answers
109 views

Does Differential Amplifier Emitter behave as ground in AC-analysis?

I am trying to solve various differential-amplifier homework problems for which I have the solution to study. For the simplicity of most problems we are able to neglect base-currents. Moreover, it ...
0
votes
1answer
231 views

How exactly are the phase shift and cutoff frequency defined for a filter + amplifier circuit?

Say we had a voltage source connected to a Low Pass RC filter and that this filter was connected to the negative node of an Operational Amplifier, so we would have a filter followed by an inverting ...
8
votes
3answers
6k views

Electret Microphone preamplification - will it work for dynamic type microphone?

I'd like to use this diagram to pre-amplify a microphone signal in order to activate the analog input of my arduino (source: reconnsworld.com) Will it work with a dynamic microphone in place of an ...
6
votes
2answers
392 views

What does the wifi amplifier exactly amplify?

The question is not exactly about the wifi, but on how does this operate in full duplex, in principle? As an practical example, lets take some commercial amplifier. As we can see from the picture, it ...
0
votes
0answers
43 views

Difficulties simulating transimpedance amplifier

I am developing a transimpedance amplifier as an assignment for a faculty course and I am running into problems when trying to simulate my circuit in ADS Keysight, even though I am quite sure how my ...