Questions tagged [class-a]
The class-a tag has no usage guidance.
20
questions
1
vote
1answer
41 views
Designing simple class a amplifier using mosfet
I'm trying to build a simple class a amplifier using a mosfet. I have read few articles about how to do it, but I'm just confused now. I'm not sure how to select resistor values. The articles I've ...
0
votes
2answers
49 views
Class A Emitter follower instantaneous power
I don't quite understand the explanation given in the book I'm reading. Why the maximum instantaneous power dissipated by Q1 is P=2Vcc*I at RL open? Also, why is the current ic1 constant I? Wouldn't ...
4
votes
2answers
171 views
Low power tube headphone amplifier design
I have never worked or even listened to tubes/valves before, so its about time I did.
I wanted a simple design to work with being my first tube project, and have found this from diyaudioprojects.com:
...
0
votes
1answer
246 views
Transformer Coupled Class A Power Amplifier
I have seen in some books, in the transformer-coupled Class A amplifiers
The transformer is connected between the collector and the VCC.
The transformer is connected between the emitter and GND (...
0
votes
0answers
92 views
Audio amplifier output bypass capacitor
I'm currently designing a single rail power supply audio amplifier and just wondering what the benifits are (if any) and if its worth including a film/poly capacitor in parallel with the large ...
0
votes
4answers
374 views
Single Supply Class-A-Amplifier circuit to amplify voltage signal alternating around ground
I have a sensor which outputs a voltage signal alternating a few millivolts around zero volts and want to design a circuit which prepares this signal for processing by a microcontroller like in the ...
4
votes
1answer
153 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 ...
0
votes
1answer
234 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. ...
2
votes
4answers
322 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 ...
3
votes
4answers
685 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 ...
1
vote
1answer
130 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
votes
1answer
74 views
How to design a simple current based class A amplifier
Very much along the lines of Class A single transistor amplifier with 2N3904, but with a current signal input. My circuit is a Zener noise source using the simplest of components. Traditional class ...
-2
votes
1answer
318 views
Why does my amplifier turn sine waves into square waves? [closed]
All photos, schematics and the ltspice simulation file are in the folder.
https://drive.google.com/folderview?id=1N1yKGnoWQoaGsuHla0DwJwF36_21ZBgX
Hello!
I have made a simple class A amplifier, but ...
5
votes
2answers
484 views
How to keep current from draining out the bottom of this push-pull amplifier?
In an earlier question I asked about driving a speaker with a BJT transistor. @Jonk offered a push-pull amplifier design of his own, and @G36 noted its similarity to the JLH amplifier described in a ...
2
votes
1answer
189 views
Class A Audio Amplifier
I am trying to design a Class A Audio Amplifier with the following specs:
9V DC Power Supply, Maximum withdrawn current 15mA
Used with a Low Impedance (8 Ohm) Speaker
Provide a minimum variable gain ...
6
votes
4answers
2k 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 ...
2
votes
2answers
4k views
Why can't class A amp drive 8 ohm speaker with just one BJT?
I designed this class A amplifier. It's my first attempt at designing an amplifier with transistors. My objective is to build a guitar amplifier with tubes, but I figured that building an amp with ...
0
votes
2answers
543 views
Can any type of op amp output stage be forced into Class A operation?
I'm trying to choose a good op amp for a Class A small signal audio amplifier circuit.
I've done my research and understand the use pull up or pull down resistors externally to force Class A ...
0
votes
0answers
143 views
Simple Class A Output Power Stage of Amplifier
I made this circuit and the output signal wasn't really what I was expecting to be.
simulate this circuit – Schematic created using CircuitLab
This is class A amplifier (both Q1 and Q2 ...
1
vote
1answer
92 views
Balanced Class A Quiescent Current Regulator (OPS of Amplifier)
In my book there is a circuit like the one shown bellow. The author (G. Randy Slone) explains the operation and performance of it but there is still one thing that left me wondering.
simulate this ...
