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)

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4answers
84 views

Does Impedance Matching Imply any Practical RF Transmitter Must Waste >=50% of Energy?

According to the maximum power transfer theorem, when a fixed source impedance is given, the load impedance must be chosen to match to the source impedance to achieve maximum power transfer. On the ...
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2answers
43 views

Microvolt to milivolt/volt amplifier with common components

Suppose one has access to common components and gear only : basic milivolt multimeter, badly regulated supply, linear regulators, 1% resistors, common BJT/FET, voltage references like LM431 or zener ...
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1answer
39 views

Why does the common collector specifically have a high input impedance?

When looking at a chart comparing different BJT amplifiers, the common collector/emitter/base, it is usually said that the common collector has a high input impedance, therefore it is suitable for use ...
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3answers
58 views

What Amplifier for Piezoelectric Ultrasonic Transducer?

first post here so feel free to point out my shortcomings. I am interested in building an Ultrasonic device utilizing two Ultrasonic piezoelectric transducers to create a standing wave between them ...
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2answers
43 views

Why is LTSpice Bode plot disagreeing with a linear plot?

Here is a picture of an amplifier that I'm simulating using LTSpice. When I insert a sine wave of 0.01 volts and 314Hz as an input, I get this: The output is taken from the collector and is ...
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0answers
44 views

Music equipment power consumption [on hold]

my friends have a band and are using 3 of these amplifiers: https://www.thomann.de/gb/tc_electronic_bh250.htm?ref=search_prv_7 Under power it says 250w but I have heard audio/music equipment uses a ...
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5answers
141 views

How to turn on LED using RF as a catalyst?

I am trying to build a circuit that turns on a LED diode when it detects AM radio waves, in order to create a "radio wave detector". Before I explain further, please note that I am not trying to ...
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0answers
32 views

Current amplifier [on hold]

Design a current amplifier with this : input impedance = 10k ohm output impedance= 1k ohm frequency = 10-100 HZ R (inner resistance) = 100 ohm voltage range = 1-10 mv current gain = 100 A which ...
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1answer
79 views

Why does this amplifier not work past a given Vcc?

This circuit works well enough in simulation, I've built it and I can't get the final stage to put more than around 16V across the load. The last stage itself is performing like a voltage follower in ...
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1answer
96 views

Am I applying the KCL the right way?

Applying KCL at the node where I have drawn the currents in order to find Vin/Vs, I am not getting the correct answer which however I did obtain using the Voltage Divider. My question is, am I using ...
4
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1answer
47 views

Presence of Crossover Distortion in Class A Amplifier

This question is about theory facts of class A audio amplifier. It is known that class A amplifier is usually biased so that an amplifier's quiescent point is in the middle of the amplifying device's ...
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3answers
140 views

Common-emitter amplifier up to 10 MHz

For sure not the first time for me visiting this awesome site, it saved me quite a few times - this time, however, I have a specific question ... would be great if someone could help me with this! I ...
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2answers
46 views

Input cap of power amp affecting power supply loop compensation?

I have a TPA3221 power amplifier powered by a TPS55340 30V Boost converter. The boost converter datasheet provides very a specific formula for calculating the loop compensation parameters, based on ...
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1answer
33 views

Simple 12V preamp circuit before speaker

In my apartment building, we have an intercom system with one central unit and multiple terminals, one per apartment. Unfortunately, after some unknown tweaks done a couple of years ago to the central ...
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1answer
39 views

seek resources in design amplifier [closed]

I'm an electrical engineering student in my summer training. My adviser is busy, so my training is self-learning, I'm supposed to learn RF circuits, ADS, and finally, design an amplifier do some cool ...
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1answer
63 views

basic DIY function generator and scope

I'm currently traveling and only have access to basic parts (soldering iron, an arduino nano and a breadboard!) but I'm able to buy parts from local suppliers. for a project I need to be able to ...
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0answers
44 views

Opamp isolation resistor calculations for a capacitive load

I want to add a capacitive filter for pulse shaping to the output of a transimpedance amplifier using an OPA847. Without the filter, the amplifier works great. With the filter, I get some ...
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1answer
41 views

Use SR 830 lock-in amplifier to detect the second harmonic component with respect to an external reference

I have a sine wave external reference at frequency f0, which is connected to BNC REF IN. The response signal is fed into input BNC A/I, I want to detect the second harmonic component in the input ...
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1answer
31 views

Power Amplifier Modification

I am trying to build this amplifier. Looking at the diagram, am pretty sure how it works, but is there a way I can modify this variable resistor with some fixed ones?
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1answer
72 views

Why rectification amplifies signal? [closed]

why a thermionic valve can amplify an electric signal (for instance, a radio wave or AC), by removing half of its phase? In other words, how is it possible that half-wave rectification can amplify the ...
3
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1answer
80 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 ...
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3answers
97 views

How to bias BJT base voltage in a push pull amplifier AND control current gain

I am building a motor driver and using the push-pull arrangement shown. I need the output signal to be +/- 30V so each 'side' should be +/-15 and are balanced. Cutting to the chase I can't get my ...
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0answers
21 views

Current mirror loaded differential amplifier with gate of current source as output

I'm trying to calculate the gain of this current mirror loaded differential to single-ended amplifier with output on the other side as opposed to the usual configuration. My result is 1/2 gm_N1(ro_N1||...
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4answers
125 views

Why is the audio input from the microphone connected to the inverting input on the TPA6111A2?

As far as I know, when we connect a signal to the inverting terminal of an op amp, we get an amplified output which is 180 deg out of phase from the input. Going through the datasheet of TPA611A2, the ...
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2answers
87 views

What are the functions of these capacitors in this circuit?

In the first picture, the capacitors are used in driving an inverter. In the second one the capacitor is used at the input of an amplifier. What are the functions of each capacitor?
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0answers
52 views

Designing a 4053 IC robotic control circuit for interfacing with Sabertooth motor controller?

I am designing a control circuit for a robot and was recommended to use a 4053 IC to achieve analogue multiplexing. PROBLEM The Sabertooth 2x60 motor controller I am using is running in analog ...
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2answers
34 views

Audio amplifier mono operation and power consumption

I'm looking to use a PAM8406 in Class-D mode, with only the left channel active. The datasheet doesn't discuss how to handle unused pins for the right channel to "deactivate" that half of the amp. ...
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3answers
889 views

Non-inverting amplifier ; Single supply ; Bipolar input

I am working on the non-inverting amplifier using a single supply, which can amplify bipolar input signal. Non-inverting amplifier is working fine without any issues, only the negative portion of the ...
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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 ...
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1answer
48 views

Class D Amplifier with Inverting Logic [closed]

If a class D amplifier had an additional logic input which was used to indicate that the amplifier's output should be inverted, could one use this signal to swap the logic of amplifier's switches so ...
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0answers
21 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 ...
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0answers
23 views

Amplifier Transfer Characteristics

In a previous question I had this as the given: The transfer characteristics of a voltage amplifier are described by the following equation: vO = F + G vI with amplifier saturation levels at ...
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2answers
55 views

UCC28C42: TI simulated ,Resistor Heated

I am using an UCC28C42 in my circuit. I need a clarification of some resistor. I am converting 48V to 24V. If my load increases to 4.5A then Resistor is getting heated up.(Circled part) I used ...
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0answers
37 views

Can I use BTL audio amplifier IC in single-ended output configuration?

I am designing a widget that has to have a speaker output (low power, between 1W and 2W, 8 Ohms, low-quality) with the limitation that one end of the speaker must be grounded. There are lots of audio ...
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2answers
59 views

Double Balanced Mixer

Consider this double balanced mixer: Its output contains only the frequencies generated by the product of those of LO and RF signals, where LO is supposed to be a large signal (which switches ON and ...
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1answer
40 views

Finding the sinusoidal input voltage of an amplifier

An amplifier has a linear transfer characteristic passing through the origin (0, 0) and with output voltage saturation at L+ = 10 V and L– = –8 V. The amplifier gain is 100 V/V. What is the ...
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1answer
36 views

TDA1904: Output volume is not amplified

I have created this circuit on the breadboard. Circuit Page no.4 of this TDA1904 datasheet: Supplied voltage 10V from pin2 and supplied signal from 3.55 mm jack to pin8. I have connected the wires ...
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2answers
111 views

Class A Audio Amp - Improving Efficiency With A Mosfet CCS

I'm designing a class A audio amplifier but am struggling with the efficiency of my circuit. I know of 'push-pull' Class A designs, but only want to use a single output mosfet. I would like to hit a ...
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1answer
37 views

Amplifier Voltage

I'm studying for my electronics exam and for this particular problem I have: Av = –85 (V/V), Ap 21 (dB) power gain, Ap = 3.41 (W/W), L+ = +9 (V), L- = -6 (V). Now the next exercise asks that: ...
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2answers
40 views

2VCC in a BJT C.E. amplifier

It is known that it is possible to get 2Vcc output voltage in a BJT Common Emitter amplifier by using an RF Choke (instead of a simple resistor) connected to the collector. Precisely, we will get at ...
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2answers
61 views

differential amplifier gain

i know that the differential gain of the differential amplifier ( mosfet or bjt ) is _gmRc or _gm Rd looking at the curve : if the current went down in one side and up in one side the gm will change ...
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1answer
25 views

How can i get the Q operating point of the differential amplifier?

I'm working with this type of configuration: Differential amplifier, and I need to find the current for this circuit so I can have maximum symetrical swing, and for that, I need to find the operating ...
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2answers
51 views

Stability and Positive/Negative feedback

I often read that positive feedback is used to get oscillators (since the output of the circuit is summed up to its input signal and so leads to instability), while negative feedback to get amplifiers ...
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1answer
75 views

Removing noise from TDA2007A Audio amplifier circuit

I have built an audio amplifier circuit like the test circuit in this TDA2007A datasheet I am going to use this circuit with Raspberry Pi 3B+ and going to feed sound via 3.5mm of Raspberry Pi to this ...
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1answer
63 views

How to calculate error amplifier output in amplifiers

I'm trying to derive an accurate formula for the output of an error amplifier in the class D amplifier I'm simulating. Most literature on the error amplifier/integrator in class D amplifiers glosses ...
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0answers
38 views

Designing a two stage differential amplifier with MOSFETS

As a part of a "Test you understanding quiz" i had yesterday at school were we tested our understanding of differential amplifiers and mosfets i came across a question that asked us to design a ...
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1answer
89 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. ...
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3answers
110 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 ...
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0answers
46 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 ...
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0answers
92 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 ...