Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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).

An electronic amplifier, amplifier, or (informally) amp is an electronic device that increases the power of a signal. It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude. In this sense, an amplifier modulates the output of the power supply.

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Why is it desirable in an amplifier to have high input impedance and low output impedance?

I've learned that it's desirable in an ideal amplifier to have high input impedance and low output impedance. Why exactly? What are the implications an amplifier has the opposite- low input impedance and high output impedance. I don't exactly…
Prabhpreet
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Amp measures board twist (unfortunately!)

Well, this is a toughie -- though fairly simple. Does anyone have experience with board twist affecting your circuit? We have a board design that is supposed to measure a loadcell. We have finally tracked a system accuracy fault down to the amp…
Berwyn
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What is the point of signal amplification if noise is also amplified?

Sorry for my ignorance but there's is immense effort in electrical engineering in the topic of amplification. I can understand the reason for circuits rejecting noise or filtering noise, but have difficulty to grasp the reason behind signal…
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What is the definition and purpose of a pre-amplifier?

I find in many places mentions of pre-amplifiers being used to boost audio signals prior to feeding to a power amplifier. Wikipedia's article on pre-amps gives some hints at their usage, but it doesn't really explain why it would be necessary to…
MattJ
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What is loading effect?

I have come across this term many times while studying amplifiers. How does this effect affect an amplifier circuit(or any other circuit in which it plays a role) and why is the input impedance kept as high as possible to negate it?
Infusion of Wormwood n Asfodel
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DC Biasing a signal and what prevents the signal going to the power supply?

I have seen some schematics that deals with audio inputs, with this kind of circuit to DC bias a signal. The signal enters on the left side of C and gets out on the right side of C and goes to the amplifier. But this is the problem. What prevents…
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Difference effect filter in before and after amplifier

Is there any difference between low pass filter that put before amplifier and after amplifier? Which one is good for PC audio amplifier?
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Amplification without transistors or tubes?

Are there any means or technologies that can be used to linearly (or close to linear) amplify an audio or LF RF electrical signal that do not require transistors or vacuum tube technologies? (Or equivalent tech such as ICs, photo-transistors,…
hotpaw2
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Can a linear amplifier have finite bandwidth?

I am reading Sedra and Smith and just want to be sure that the following characterization of an ideal linear amplifier is correct. A linear amplifier was defined as an amplifier for which the output signal is proportional to the input signal given…
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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 need a software-tunable oscillator with…
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My amplifier produced a negative gain when it should be positive. Why?

Disclaimer: I am a Mechanical engineering student and I don't have a huge background in electrical engineering. In on of my lab classes, we just dealt with the response of amplifiers to a variable DC voltage source. The lab consisted of DC power…
Greg Harrington
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Why doesn't my transistor audio amplifier work?

I'm a newbie to transistors. Could anyone explain why my set up doesn't work ? The transistor is a 2N2222 NPN BJT, and the microphone is just a standard earbud. The loudspeaker is just one I ripped out from a toy.
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AoE3: Grounded Emitter Amplifier Distortion

I'm trying to understand a passage in the 3rd edition of Art of Electronics which explains the distortion of grounded emitter, common collector amplifiers vs. those using an emitter resistor (ch. 2, pg. 95, left column). It defines distortion as the…
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Single Pole Amplifier

My text book says, "Single Pole amplifiers are always stable,hardly surprising, because in the worst case it can never go beyond 90 degrees." But it did surprise me and I cannot figure out why a single pole amplifier cannot go beyond 90…
Anuroop Kuppam
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Electrical amplification of 10ns pulses without "ringing"

I have an expensive arbitrary waveform generator (AWG) that can create very clean arbitrary pulses. I am producing gaussian pulses from this AWG that are about 10ns wide, which look like this on a scope: The AWG has the drawback of only being able…
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