Questions tagged [power-amplifier]

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3
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1answer
79 views

what is the difference between these two configurations?

I can understand this circuit configuration: But i don't understand when signal is placed in Qp's base. In this configuration we don't have VBB/2 in the two base... Sorry about my english and thanks ...
0
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2answers
32 views

Maximum Gain and Maximum Power Transfer

I am a bit confused about Impedance Matching for maximum gain and for maximum power transfer. I knew that the conjugate matching between, for instance, an amplifier's output port and a load Zl, is ...
0
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0answers
20 views

Question about pins on TCA940

So for the sake of learning i got this 10 watt audio amplifier and i wanted to see if i could make things work but i'm not sure what some of the pins are used for. Pin 5 "Compensation": From what i ...
4
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2answers
95 views

DC on op-amp input, audio amplifier

I have built the following audio amplifier circuit on a breadboard. The circuit works. However the circuit makes a DC offset on the non-inverting input of the op-amp. simulate this circuit – ...
0
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3answers
64 views

How to match a power amplifier and a loudspeaker array?

I am trying to use a power amplifier that is available to me to actuate an array of loudspeakers. The array has a total number of 30 loudspeakers (ways of connection can vary). And I would like to ...
0
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1answer
90 views

Class F amplifier analysis

I can't figure out why drain voltage is rectangular in the following circuit: I tried this: $$ V_{ds}=V_{DD}-I_{fund}R_lsin(\omega_0t)-I^{(2)}Z_{in}^{(2)}sin(2\omega_0t)-I^{(3)}Z_{in}^{(3)}sin(3\...
0
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1answer
90 views

Power amplifier design

For my research purpose, I am planning to design one power amplifier (basically, a current amplifier) with the following specification- Frequency range: 0-100MHz (or at least 0-30MHz) Output voltage: ...
0
votes
1answer
75 views

Amplify Arduino Due DAC output

I need to drive an inductive load from an Arduino Due analog output. The analog output delivers 0.55V-2.75V (yes, it doesn't deliver 0 volts). I need to get something like 0-14V with up to 3A ...
1
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0answers
50 views

How does speaker in “ROBOCOPP B A S U Ealarm SOS Personal Alarm” works?

I was working on a project which required producing a sound with more than 125 DBs...then I found this device in market which claims of producing 130DBs although to my knowledge it produces around ...
2
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1answer
54 views

Improving Power Amplifier - Digital Bias current set

In the following power amplifier: the MOS bias current is set by VR2. T4 acts as a temperature balance. The ensemble R15, RV2, D5, T4, T5, R14 act as a current source. VR1 act as offset adjustment....
1
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1answer
38 views

Calculation of DC power drawn by circuit in Class A power amplifier

simulate this circuit – Schematic created using CircuitLab I'm watching Prof. D.C. Dube's lecture (timestamp included) on power amplifiers, and I'm confused about the calculation of DC power \$...
0
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1answer
110 views

Unexpected loadline in ADS simulation

NOTE: This question is related to a homework project. I’m designing a PA for the 850-880MHz band. We have quite a lot of freedom for doing that. Only two requirements are specified: The amplifier ...
0
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0answers
43 views

how to enlarge the reading range between the 13.56MHz NFC reader and tags with ISO15693?

I use TI devices, DLP7970ABP and RF430FRL152H tag. In order to enlarge the reading range, I buy a power amplifier and a large antenna(430mm*330mm). If I only disconnect the original antenna on the ...
0
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0answers
43 views

Add IR (infrared) remote control to simple audio amp?

is it possible to add some kind of a remote control receiver to a basic audio amp board that only has a manual volume knob? The IC chip in the amp board is a TDA7498. A general view of the board is in ...
0
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1answer
102 views

Isolated High Voltage Amplifier Idea

Test laboratory of our factory asked me to design an isolated high voltage amplifier. Here are the requirements: The circuit will be built with transistors and passive components in the lab. (No IC ...
1
vote
1answer
82 views

How do I choose the power rating of resistors in audio power amplifier?

I read a bit about audio power amplifiers and struggle to understand the power rating of the emitter (i.e. current sharing) resistors in power amplifiers. I refer to this project. [EDIT: schematics ...
1
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2answers
95 views

Why should the bias servo transistor not be placed on the main heat sink for a Sziklai pair?

The Wikipedia page on Sziklai pairs contains the following statement (emphasis mine) Sziklai pairs can also have the benefit of superior thermal stability. [...]. [Q]uiescent current is much more ...
1
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1answer
49 views

Power amplifier shows 0 input and output resistance

I have a non-functioning transmitter for a radar I've built. When I was checking for shorts using a multimeter, I noticed that the resistance measurements between RFin and GND and RFout and GND of my ...
0
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1answer
66 views

alternative amplifier for vibration exciter (shaker)

I am using a second-hand LDS V201 permanent magnet shaker, and would like to use this to test and validate some monitoring equipment. I would like to generate signals suchs as sweep sines, but these ...
0
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1answer
35 views

Calculate input resistance of power amplifier

how can I calculate the input resistance of this circuit? Thank you!
1
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0answers
59 views

Amplifying pulse signals causing pulse lengthening problems

I am currently trying to design a circuit that would sense a voltage change at its input, convert that change into rapid "on"/"off" change at output and amplify same switching voltage to high current (...
0
votes
2answers
164 views

Power Amplifier (Darlington) with Power and current limitation

I'm designing a power amplifier and the following circuit is the output stage. My output stage consists of two complementary transistors for both, positive and negative waves but for better ...
0
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3answers
141 views

Power amplifier, does this circuit work?

I found that circuit for a power amplifier. Does it work? I want to build one for myself.
1
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0answers
57 views

Built-in power amplifier of the ST7580

The ST7580 is a power line communication device that can be controlled with any host controller. The ST7580 has a buil in power amplifier to allow it to send a modulated signal (0Hz to 250kHz) as far ...
2
votes
2answers
283 views

What's wrong with my1943/5200 Mosfet Amplifier? Blown on first run

I have just brought an 1943/5200 mosfet based amplifier board. Shopkeeper said it's rated for 24-0-24 AC. So I connected it with 24-0-24 transformer like this in image below. As soon as I turned the ...
2
votes
2answers
64 views

Question about the power rating of a RF power amplifier

In HMC453ST89's datasheet, it gives the electrical specifications when Vs = +5V: The max. output power is around 32.5dBm, about 1.6W. But for a 50 Ohm load, 1.6W means the peak voltage is about 12V. ...
0
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1answer
82 views

How close to P1dB can I go?

I'm trying to decide on a safe input power to a power amplifier. The amplifier in question is SE5004L. The datasheet specifies that the amplifier output 1-dB compression point has a minimum value of ...
-2
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2answers
111 views

Stk086 distance between pins? [closed]

I have been trying to make a footprint for this IC, and trying to figure out the distance between pins, it is a 10 pin ic what do you think the distance will be? What is the normal distance between ...
1
vote
1answer
589 views

IR2110 driver output causing shoothrough despite deadtime

I'm having trouble with the ir2110 output. I'm working on a class d full bridge amplifier and I use 2 ir2110 to drive 4 irf540N mosfets. The switching frequency I use to generate the PWM is 240kHz and ...
0
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2answers
110 views

How to design and build RF amplifier, that work in 450Khz [closed]

I have a schematic, that is a sine generator and mixer that does AM modulation. How to design and build an RF power amplifier and build a compact antenna. The goal is to transmit signal up to 50 ...
0
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2answers
81 views

Maximum output power of a PA

I was discussing with a friend about maximum output power of a (class A/B power) amplifier (for example if the device following the PA can only tolerate a certain amount of power). If the input power ...
1
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2answers
702 views

Biasing Class AB power amplifier with MOSFETs

I am having trouble getting the resistor biasing to meet a minimum 1.25W at the output: Note, the distortion and watt meter. I was told the SPICE parameters for the FETs didn't really matter. (...
0
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2answers
74 views

Understanding of class-AB currents

I am trying to understand a simple class-AB output stage. The bias voltage for the transistors is made by using two diodes. The following picture show the circuits. The currents drawn are how, i ...
1
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2answers
277 views

Design a tank circuit for class C power amplifier using ADS

I am trying to figure out the best values for the tank circuit values (L and C) in order to compare the amplifier's efficiency with the output power I have chosen the tank value L1 and C7 to resonate ...
0
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1answer
32 views

Vibe Table: Increase Peak Force Output?

I'm driving a small, benchtop vibe table (shaker) with two Crown DSI-1000 PA's, and also cleaning my signal with a DBX 231s EQ. Currently running the system at 6.8 GRMS, but I'm looking to increase my ...
2
votes
0answers
405 views

TDA7294 100W Audio Amplifier Causing Unexpected Problems

This is the circuit I will be referring in this question: TDA7294 is described in this data sheet. Upper IC with added external components is a well-known circuit and can be found on many websites ...
1
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1answer
107 views

RF power amplifiers and preventing damage when the antenna is disconnected

I'm looking at Wi-Fi 2.4 GHz power amplifiers and I can't find a single high power (500 mW) one including a system protecting it from damage. I can, for example, find some ~ GHz PA with protection ...
0
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1answer
46 views

AWR PA Output Power Simulation - Credible?

I'm working with the SKY65111-348LF power amplifier from Skyworks and wanted to obtain some idea of its performance using AWR Microwave Office. I'm not sure if my process is correct and wanted to have ...
1
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0answers
500 views

Increase output power of simple class AB audio amplifier

How could one increase the output power from a class AB amplifier circuit like this one? I wish to increase the output power to around 2W. The above picture is simulated with a 200mV amplitude, 5kHz ...
0
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2answers
61 views

Conventional current in a power amplifier?

I recently learned that electricity doesn't actually flow from + to - but the other way around.. So my question would be: if I was using a 2 channel power amp and connected a speaker to it with the ...
2
votes
2answers
177 views

Resistor network in between SAW Filter and Power Amplifier

I am going through user guide of Microchip's LoRaWan Gateway. The manual is over here. At page 48, I am struck at one resistor network and unable to understand it's ...
2
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2answers
121 views

Can someone help me with this power amplifier problem?

Wire the circuit shown:

 R1 = 68KΩ R2 = 10KΩ R3 = 10KΩ R4 = 200Ω ( two 100Ω in series ) R5 = 2.2kΩ C1 = 0.1 µF C2 = 0.1 µF Q1 = 2N3904 
 Set the sig. Gen to 50mv RMS.  With frequency ...
0
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3answers
318 views

15-20W amplifier circuit

I'm trying to build a small radio amplifier which will deliver around 15V at 1A at 250kHz from a 0.2V input of the same frequency. I have searched for and tried as many online circuits as I can which ...
6
votes
4answers
1k views

BJT base connected to ground and still operates?

When in university I used to get confused how a transistor (NPN) can draw current from ground. I'm now studying power amplifiers and again, this same configuration appears. How does Ir draw current ...
1
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1answer
663 views

Calculate the total max power dissipation in CLASS AB push pull for reactive loads

As worst case we can assume in reactive load the same power dissipation with the resistive part of that load. Thus for a 8 ohm impedance with phase angle of 60°, we can use \$R_L=0.5*R_{Reactive}=4\...
0
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1answer
56 views

Using an RF adapter to improve LTE signal in the house

In my apartment, the GSM signal is very scarce, if not absent at all, except for a few spots, where there's a decent LTE signal and I can browse internet reliably. In order to improve the reception ...
1
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2answers
395 views

Class A power amplifier: power dissipation

Let's consider the following class A power amplifier: And here is the time-domain simulation of the power dissipated across the transistor: As we can see, the power varies from approx \$0.1W\$ to \$...
4
votes
2answers
1k views

Confusion between Class B and Class AB Amplifier

I am reading about output stages of an amplifier and classes of amplifier. The following circuit is named as "Class B" amplifier. From my understanding, the above circuit should be a class AB ...
1
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1answer
302 views

What do the inductors L2 and L3 do in the following rf power amplifier circuit?

I found a circuit online about an rf power amplifier working in the 88 to 108MHz FM spectrum. The circuit diagram is shown below I understand that an amplifier needs an inductor and a capacitor in a ...
0
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2answers
310 views

Push-pull amp in class A what it mean

I take next sample schematic. This is only an output stage of any real power amplifier. It's clear when it's work in B-class the every BJT amplify only one half of input signal. But what it means if ...