Questions tagged [amplifier]
An amplifier can be used to adapt the range of a signal to a requirement, to make it more robust for transmission, or to satisfy interface requirements (like input/output impedance).
5,185 questions
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7 views
how do I make this PNP audio amp better (more power, more efficient)
simulate this circuit – Schematic created using CircuitLab I lost all my NPN transistors, so NPN transitors are not an option. Sorry!
-2 votes
0 answers
43 views
Walkman with dead right channel (Crown Japan cs-22f) [closed]
I'm trying to find out why the right channel of my Walkman is dead. The left one works perfectly. I already measured the 3.5 mm jack and all three contacts have a decent connection from the cable to ...
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1 vote
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Building a driver for a RX/TX transducer (piezo, ultrasonic)
I'm trying to build a water flowmeter using piezo transducers. These emit an ultrasonic waves - a first one with a first transducer while listening with a second, then a second one emitted by the ...
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0 votes
1 answer
104 views
Input Noise Of An Op-amp
I want to detect a 200 nVrms signal at 30 kHz. For this purpose, I will build a circuit whose block diagram is shown below. First, I will take this signal and amplify it by 40 dB using a preamplifier (...
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-1 votes
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Transistor selection in a 500mW Amp schematic
Why are these specific NPN and PNP transistors selected. Why not use 9014's and 9012's ?? Also, I see the power supply is 12 VDC. How do you calculate the output to the 8 ohm speaker? Would you have ...
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-1 votes
1 answer
195 views
Review my 5-37Hz filter and amplifer. Will it work? Am I missing any other simulation. (Made in LTspice)
Context. I am using this filter and amplifier to detect Schumann resonances. These are EM modes of very low frequency (7,14,20,28,33) of pT range. My goal is to use a copper coil sensor. These are AC ...
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0 votes
2 answers
118 views
Non-inverting DC Summing amplifier - single supply operation
I need a single-supply non-inverting summing amplifier for DC signals. Because I do not have a negative supply available, the obvious solution of using standard op-amps as inverting amplifiers seems ...
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1 answer
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Purpose and selection of inductor for RF power amplifier that has a VCC pin (MAX2616)
I am currently building an RF amplifier PCB for around ~2.4 GHz using the MAX2616, which is a broadband RF amplifier for 40 MHz to 4000 MHz. Looking at the datasheet, I am confused about the purpose ...
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5 votes
6 answers
1k views
How to measure audio frequency distortion without expensive equipment?
I'm building some BJT amplifiers, and I'm currently getting distortion values via Multisim simulations. However, I'm not fully sure about the results I've been getting, and I would like to double ...
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0 votes
5 answers
157 views
Can I use OPA2227 to Make Low Pass Filter and Amplifier with Gain of 50~100
I am looking for low noise opamps and the one that caught my eye was OPA2227 and is available locally. Its a dual opamp and was wondering to use it for the as low pass filter with cutoff of 38 Hz and ...
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2 votes
1 answer
167 views
Current Mirror In Differential Pair Amplifier
I am designing a differential pair that is connected to a current mirror. I have calculated the drain resistors of the differential pair to draw around 16.5 mA and achieve a gain of 20 dB. When I ...
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1 vote
1 answer
98 views
Trying to limit the current going through a transformer coupled to a Piezo Speaker. Why is the speaker louder using an Saturated NPN transistor?
I'm working on a project where I need to update an existing design to resolve an issue with the audio amplifier circuit overheating when the volume is set to HIGH. My approach was to replace the NPN ...
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5 votes
5 answers
1k views
How is the 4.5V delivered in this charge amplifier circuit?
So I have found this circuit from this website: https://sound-au.com/project202.htm As you can see in the picture there is the 9V battery powering the omp amps, but for the +4.5V, how is that ...
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4 votes
4 answers
1k views
Why is amplifier bandwidth defined at −3 dB?
Why is the voltage amplification factor of an amplifier or a filter generally expressed by its gain in decibels, and why is the bandwidth of this amplifier defined at −3 dB?
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1 vote
1 answer
129 views
Pull-pull and push-push amplifiers
I know about push-pull amplifier stage, but recently I came to know additional configurations like push-push and pull-pull stages, from a question I was solving. But couldn't find any sources about ...
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