An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the power of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is a circuit that has a power gain greater than one.An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For example, audio amplifiers amplify signals in the audio (sound) range of less than 20 kHz, RF amplifiers amplify frequencies in the radio frequency range between 20 kHz and 300 GHz, and servo amplifiers and instrumentation amplifiers may work with very low frequencies down to direct current. Amplifiers can also be categorized by their physical placement in the signal chain; a preamplifier may precede other signal processing stages, for example. The first practical electrical device which could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Today most amplifiers use transistors.
hello all
i wanted to make a circuit that takes power from the main a.c supply and increases its frequency( from 60 or 50Hz to about any frequency (lets say about 150KHz? or 15KHz?)), but the output voltage should not drop less than about 25 or 30v...
Hello everyone,
I could not find the solution for my problems by searching the forums. Thus I am writing them here so would you guys please help me.
There are two problems but it is not good to create two topics for this so I combine them here:
1. High Voltage Amplifier:
We often work...
Gentlemen and ladies,
I have an RF device and an in-line amplifier (specifically an AMMC-6220 - http://www.datasheetcatalog.com/datasheets_pdf/A/M/M/C/AMMC-6220.shtml). Certain units develop gain spikes at the high-freq band. They are in very specific frequency locations, and vary in amplitude...
why is an inverting amplifier and not a non-inverting amplifier used as a summing amplifier ?
Why must the input voltages be inverted in a summing amplifier ?
I am told that a summing amplifier is used as mixer in concerts where different music produced by different instruments go through...
I have been given a basic electronics project for design of a single stage common emitter amplifier. The problem is that this the first time I am going to carry out such an assignment and have no idea how to start. I do not know how to make choice for the resistors and I need help in this...
Homework Statement
The picture is an closed loop amplifier, the question is simple: find the closed-loop voltage amplifier of the circuit
Homework Equations
Av = v0/v in = - (R2/R1)
The Attempt at a Solution
If R2 is just simply a bunch of resistors connecting crazily, then...
I am trying to chain two op amp amplifiers. I thought that I could couple them through a capacitor so the output offset of the first amplifier doesn't get amplified. Now the first one is oscillating because of the capacitive load. Is there a way to do ac coupling without using a capacitive load...
Homework Statement
Given the attached figure (with values as shown on the op-amp) find Vo and io.
Homework Equations
None
The Attempt at a Solution
I figure that we're looking at an inverting operational amplifier and I used a voltage divider to find the input voltage...
Homework Statement
a differential amplifier with differential gain Ad = 20000, is used for amplifying signals obtained from an electrocardiogram. If the input terminals are connected together and 1V signal is applied to them, an output signal of 0.05V results. Calculate the common-mode-gain...
Hello all,
This is my first post in this forum. Hope can get some constructive help from the community.
I did some testing with some radios which is actually a double ended circuit (BTL), meaning it has the spk+ and spk- port.
When I want to connect it as a single ended circuit, meaning...
I severed the power cord to an amplifier of mine and I am trying to replace it. My amplifier seems to have a pretty standard 3-prong power cord. Printed on it is:
E88265-C SVT 75 degree celcius 18AWGX3C VW-1 CSA TYPE LL81924
I googled some of these part numbers but none of them seem to...
hiii guys
im doing my FYP on amplify the voltage from a rogowski coil
just to make it short
i have already design the coil
which can detect a 50k frequency and gives pick-to-pick = 10mV Ac
now, i have to design an amplifier that can give an actual value.
so, i have already got a...
hi,
I am interested to know how the lock in amplifier works?
It is very commonly seen with oscilloscope, but I fail to grasp the idea behind it?
I would appreciate any lecture notes or sites which give clear and precise understanding of it.
Thanks
The question is:
To tell you the truth I don't know where to start, I have read over all the teacher's notes and the chapters in the book, and I haven't seen a question similar to this at all. I am not even sure I quite get the question. Can someone help get me started please?
Thanks!
Can someone please explain to me with what reasoning RL and RC are taken to be in parallel when calculating Vo for any decrease/increase in IC (DC) due to isig (ac)
Thank you
Hi
I've built what is meant to be a non-inverting dc amplifier using a 741 op-amp (shown in attached diagram). Resistor values are: R0A= 470k, R0B= 47k.
I am feeding the op-amp a supply voltage of 12v and an input voltage to the non-inverting input of 0.5v. According to the resistor values...
Hey there.. this is my lab discussion.. which i'll attend it this coming monday..
however.. there are questions that I'm not sure the formula to calculate it..
i really hope u guys can varified or corrected my formula.. =)
Homework Statement
Vin(pp) = 1.0V
is it Vin = Vin(pp) / 2 ...
I am interested in attempting to build a home theater amplifier, but I have a few questions. What is the voltage range from the audio outs on something like a DVD player or processor? Also, what is a typical current or voltage range from the speaker connection terminals?
Hello All,
I am faced with a very interesting challenge and I'd like to see if you all could give me any insights. I'm currently planning to design a linear power amplifier loosely based on the design on page 22 of this PDF file here...
Hi,
as mentioned in my previous thread, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital (software) version.
I know 'nothing' about EE, I'm a Computer Science guy, so hopefully this question is not too easy :-)
This...
"VOLTAGE-CONTROLLED AMPLIFIER". I am required to build a voltage-controlled amplifier
Homework Statement
"VOLTAGE-CONTROLLED AMPLIFIER". I am required to build a voltage-controlled amplifier,using:
1 operational amplifier(741), 1 capacitor between 1 to 10 microfarad(Electrolytic polarised...
Hey all,
So I am a Senior in college, enrolled in a microfabrication lab. We have a final project to do and we're already being asked to come up with all of the design and physical sizes along with beginning simulations. The reason is so we will for sure have everyone's design by the time...
Hello,
I'm sure it will be easy for someone to answer. I have an amplifier circuit running in multisim and it's drawing around 9mA of current, 25VDC. Am I right in thinking that the circuit will only draw as much current as needed from the transformer, and a 25v 2A tranny would work to power...
Hi there. I currently have a system that is about to have a load cell installed. The output of the load cell with the 15V excitation voltage will be 0-30mv (2mv/V sensitivity). Now forgive me for asking, as I am not knowledgeable in this area (I have some electronics background, being a...
Hello all,
I'm trying to design a circuit that utilizes the http://www.analog.com/en/rfif-components/short-range-transceivers/adf7020/products/product.html" . What I'm worried about is getting everything to match properly; the PA requires a 50 ohm input, and after dropping it into the...
hi ..
i am doing a poject for my college and .. i design the amplifier
but when i connect to the speaker circuit ...of cource u konw it
npn and pnp transistor ..
the proplem is that i have to get to source on +ve and _ve
is there any circuit that i can have the right...
Transistor AMPLifier HelP !
could some1 explain it entire circuit in terms of electron movement i.e how the voltage drops in each component in terms of electron flow
1)i can't understand the voltage divider bias i find it extremely difficult
please explain it interms of electron movement in...
Transistor AMPLifier HelP !
i will start from the first
please clarify my doubts
i will post my other doubts as and when i get replies and answers
my first doubt is
what is meaning of Vbe base emitter voltage
and also Vce collector emitter voltage
what is the actual meaning of these...
I am undertaking a question that requires me to calculate the number of optical amplifiers that are needed to ensure that a light signal is of sufficient enough power to be read and understood at the receiving end. I have the maximum potential power input, the minimum required output at the far...
I was wondering what's the main advantage of choosing one over the other, besides common drain having to suffer body effect. How do we determine if a CC is better or a CD is better to use as a buffer?
I've made a single opamp amplifier for a mic but it has this problem, when I play a very low
200hz tune the output of the opamp shows 6 mV and another 200hz tune at higher volume shows a 600 mV output, the problem is that if the loud tune is ON the low level tune doesn't make any difference...
Hey guys.
I want to design an AC coupled amplifier, to be powered by a 12V supply. The input voltage should be less than 30mV and the gain of the circuit should be 24dB. The circuit has 2 stages with the gain of the 1st transistor amplifier being used to amplify the signal going into the 2nd...
hi everybody
i have a term project , where i am supposed to design an optical communication system of 10Mbps , a BER of 10^-9 , a sensitivity smaller than -15dBm . i have designed an optical Rx with a transimpedance amplifier , post amplifier ( differentiator in this case , to compensate...
Hello,
First thread on this forum! Thank you for giving me you're opinion about a question that I have.
I am using a data acquisition system (ADInstruments Powerlab 16/30) to record muscular activity from electrodes. So far, everything is working properly.
I recently got an approval to...
Homework Statement
I need help! My teacher just assumes I know everything and he doesn't "teach" me very much. He expects me to a) determine characteristic equation of a MPF102, but I don't understand how to do it...when I ask he just says, "go have fun with it" It might be fun if I...
I know this is a school type question, but it's an example problem whose solution is already given and it's the solution I am unable to understand...
Find the current gain of the following circuit.
http://img17.imageshack.us/img17/2389/opamp.png
Solution: As the input signal Vi is connected...
I want to learn how a cascaded common emitter transistor amplifier is modeled. I also want to know how all the calculations are done with regards to current and voltage gains, input and ouput impedances. I want to also know how we do the calculations with and without the emitter reistor. Can...
Greetings. I am trying to understand the common base amplifier better so I can build a preamp for a low impedance guitar pickup. In order to explore its operation, I tried to model it with the "approximated" Ebers-Moll model (from the wikipedia page on BJT's) and the graphing program in Mac OSX...
Hi everyone. I'm working on a project where I'm using a current controlled differential amplifier as a VCA followed by an op amp in a differential amplifier configuration with gain. I'm using the op amp to make up gain, because I'm dividing down the input signal going into the VCA stage by...
Hihi,
I put a photodiode's legs to both the input for a differential amplifier
http://en.wikipedia.org/wiki/File:Op..._Amplifier.svg
Then, the voltage difference of the photodiode is amplified and its output is then connected to a resistor which is not shown in the above picture. The...
I am trying to understand the derivation of a logarithmic amplifier as shown in the figure attached.
The diode has a non linear characteristics represented by V=ClnI,where C is a constant.
Then since the current through the feed back loop is the same as the current through the input...
I need a help with lock in amplifier. I want to measure third-harmonic voltage from lock in amplifier. I have metal liner on a film on the substrate and I pass ac current through this metal liner which acts both as a heater and a thermometer. I want to calculate the third harmonic voltage from...
HI
i know that the circuit attached to this thread is a differential limiting amplifier , and the collector of Q2 acts as a current source , but other than that , i can't get my mind around it ! P1 is the input , P5 is the output , and Vcc is +12 connected to the 27 R .
could someone...
Hello All,
I'm working on designing a simple circuit that takes a square wave clock input and converts it to a sine wave using a Johnson Counter, an R2R ladder and an output filter capacitor (see the below link for reference)...
Homework Statement
The question is about the concept of the operational amplifier in electronics.
For an ideal op. amp., it is said that the input impedance is infiinite and the current allowed by the op.amp. through its input terminal zero or in the case of a practical op.amp., it is...