Questions tagged [class-b-amplifier]
32 questions
10
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6 answers
Difficulties with Class B Amplifier Biasing
Here I am referring to class B output power amplifier.
This circuit should be easy to build and understand but I'm having problems with biasing since I don't really know how to bias the bases of Q1 and Q2, so that Q1 would conduct only positive…
Keno
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3 answers
Input coupling to Class AB amp with diode bias. One capacitor or two?
When AC coupling the input signal to a Class AB (Push-Pull / Complementary Pair) which is diode biased I see two different approaches:
Signal connected between biasing diodes with single decoupling capacitor:
Signal connected directly to each…
Frosty
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10
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1 answer
7
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2 answers
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 amplifier. Because we have a constant biasing, so both…
sundar
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7
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3 answers
Highly Distorted Output of Class B Power Amplifier
This is the circuit I made:
simulate this circuit – Schematic created using CircuitLab
This simple circuit incorporates differential stage - VA (Voltage-amplification) stage - OPS (Output Power Stage). Open loop gain is high, closed loop gain is…
Keno
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5
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1 answer
use of diodes and resistors in a push-pull amplifier
I am a beginner in electronics facing a bit more difficult problem.
what might be the function of the two resistors(R4,R5) and diodes(D1,D2)? in the circuit below?
Hilton Khadka
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4
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2 answers
Question about Class AB amplifier
In class AB amplifier, we introduce two 0.7V sources to avoid cross over distortion.
To do this, we use diodes, all of the circuits employing diodes look like,
My question is, why aren't they like this (down)
In the original circuit, doesn't a…
Aravindh Vasu
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4
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1 answer
How can I minimise the power consumption of this crossover clipping circuit?
I am trying to produce a circuit that produces crossover clipping distortion for musical purposes (to sound like a crappy old transistor radio). The problem I am running into (among a few, but to limit the scope) is that to observe clipping…
loudnoises
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3
votes
3 answers
How does this Push-Pull amplifier work?
I'm reading about op-amp circuits that use negative feedback from this article (question no.19).
What confuses me is that the negative feedback for the Op-amp (which is being used to reduce cross-over distortion) is given directly from…
Sumanth
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3
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1 answer
Problem with a class AB amp
I have a simple preamp circuit coupled with a class AB power amp. The design is quite simple and I am pretty sure I already made it work a couple of years ago.
simulate this circuit – Schematic created using CircuitLab
The power transistors are the…
Doombot
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3
votes
1 answer
How to determine current limiting resistor values for push pull amplifier driven by op amp?
I'm looking to increase the output current drive of a high voltage op amp using a push pull amplifier. The OPA454 datasheet includes an application circuit to do exactly this, and includes some current limiting resistors:
As noted, \$R_3 =…
Null
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2
votes
5 answers
Design of a discrete BJT current buffer for low-current op amp
I built and simulated this BJT current buffer for an opamp based on examples I found in various places online:
Link to simulation of above schematic
It simulates fine, but I am pretty sure it will not work as drawn in practice. For one thing, any…
Frosty
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2
votes
2 answers
Understanding harmonics of different Amplifier Circuits (A,AB,AB w/OP-Amp)
I have been test the circuits for amplifiers and got somewhat stuck in understanding the results for the FFT's harmonics.
With a standard type B I was able to get this graph for the harmonics
for this circuit
In here I seem to get quite a few…
Zaid Al Shattle
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2
votes
1 answer
Class B power amplifier using only Nch FETs
I'm building a combined linear regulator/electronic load. When the output is lower than the supply Q3 acts as a linear regulator and when the load tries to pump power back the other way, Q6 acts like an electronic load. It's basically the output…
Sam
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1
vote
2 answers
Single rail power to balanced
EDIT:
I built up the circuit shown below. I had the power transistors lying around, as they're a type used for class B audio amps, and they're dirt cheap on the "jungle river" website--about 12 bucks for five pairs. Without heatsinks (which clearly…
Toby Eggitt
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