Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [amplifier]

An amplifier can be used to adapt the range of the signal to a requirement, to make it more robust for transmission, or to satisfy interface requirement (like input/output impedance)

0
votes
0answers
12 views

micro level voltage signals

I am currently doing a project in which I have to measure micro-level voltages (body potentials) and show the signal at the output of the amplifier. I have used INA128 from TI as my first project with ...
0
votes
1answer
37 views

How to simulate the exponential growth op-amp?

According to Wikipedia, the following is the exponential output operational amplifier. I would like to test this out in a simulated environment and see how this functions. For example give a sine ...
0
votes
0answers
45 views

Digital drop-in replacement for potentiometers

I'm looking to replace the potentiometers in a guitar valve amplifier with digital counterparts, to vary the controls with a microcontroller. Motorized potentiometers are not a solution due to the ...
-2
votes
1answer
56 views

Newbie question: Feasible way of amplifying 100+ channels of slow and low amplitude signal

I want to amplify signal coming in hundreds of channels (sensor array each producing a very low amplitude 30-200Hz signal). For every channel i care only about intensity of the signal (i don't need ...
2
votes
2answers
73 views

What's wrong with my1943/5200 Mosfet Amplifier? Blown on first run

I have just brought an 1943/5200 mosfet based amplifier board. Shopkeeper said it's rated for 24-0-24 AC. So I connected it with 24-0-24 transformer like this in image below. As soon as I turned the ...
0
votes
3answers
103 views

Why is the maximum efficiency of a push-pull amplifier 78.5%?

One of the practice questions for my upcoming test is this: After some googling, it seems like the correct answer is A. But why?
0
votes
1answer
25 views

Input Resistance and Mid-band Gain of a CE-CE Stage Cascade Amplifier

I am trying to calculate the Input Resistance and Mid-band Gain of a CE-CE stage. Here's what I got so far: I am having some doubts regarding my calculations though. Mainly with the input ...
0
votes
2answers
57 views

Why don't I get a signal on the load?

I don't get any signal on the load, what am I missing? Shouldn't it amplify the input signal? I have 50mA from the current mirror, the Vbe on Q10 and Q11 is around 0.75v
-3
votes
0answers
51 views

Designing a two stage transistor [on hold]

Ive been completely stump on this problem here, any help would be greatly appreciated! Design a two-stage transistor amp with a differential input and a emitter follower output. The amp should have a ...
0
votes
1answer
61 views

Three stage amplifier

Well I need to design three stage amplifier Im stuck on the output stage, I need that the AC Current on the load will between 20mA to 100mA, but Top current I get is almost 5mA, cant over pass it ...
0
votes
0answers
34 views

To use a LM392 do Operational Amplifier and Voltage Comparative [on hold]

The LM392 consists of two independent building-block circuits. One is a high-gain internally-frequency-compensated operational amplifier, and the other is a precision voltage comparator. May I use ...
0
votes
0answers
29 views

Solving the MOSFET, using KVL?

The question is Find VD and ID? The FET has Vth = 1.0 V and k(w/l)= 1.0 mA/V2 and λ = 0, VDD = 5 V. My question is can I use KVL like this Vdd - R1 ID - R2 ID - R3 ID =0 rearranging for ID = 11/5? ...
-5
votes
0answers
39 views

Cascaded Amplifiers & Constant Current Source [on hold]

this is regarding my Chegg homework help. So far no one has been answering me yet :( Can anyone help? I need to hand in these questions tomorrow https://www.chegg.com/homework-help/questions-and-...
-2
votes
2answers
67 views

Stk086 distance between pins? [on hold]

I have been trying to make a footprint for this IC, and trying to figure out the distance between pins, it is a 10 pin ic what do you think the distance will be? What is the normal distance between ...
0
votes
0answers
41 views

Differential Amplifier Exam Problem

I am lost with how to approach part C and D of the question. In fact, I need some intuition with how to tune a differential amplifier.
1
vote
0answers
46 views

Portable Guitar Amp - Distortion, Volume & GND

I have tried following the given schematic There are 3 things I am unsure of (what I tried): The Volume 5k Potentiometer: I have tried adding a volume control to the schematic by placing the ...
0
votes
0answers
18 views

Small TPA3116D2 amp [closed]

So basically i got this 2x50W+100Wsub Tpa 3116d2 amp Now my question is since the amp has an issue that it overheats the small orange inductors even when the sound system is idling(no signal) so it ...
0
votes
1answer
57 views

How to amplify current and buffer voltage

I have a battery supplying 5V@500mAh and an LED (the load) which draws 1000mA@5V (twice the current the battery supplies per hour). I found some circuits that have NPN transistors only and other ...
0
votes
2answers
47 views

Amplifier advice for speech sythesizer circuit

I'm designing a circuit that hooks up an SP0256A speech synthesizer to an AVR microcontroller and would like some help with the audio output amplification. The datasheet describes the output as being "...
0
votes
2answers
63 views

Audio amplifier for 600 ohm headphones

I am working on a design which must drive an audio output into 600 ohm headphones (aviation headsets). Normally, I would just use an off-the-shelf class D amplifier but I can only find ICs designed to ...
0
votes
1answer
44 views

MOSFET Differential Amplifier voltages via PSpice and by hand

I want to do an analysis on a differential pair and there is a problem when the pair is in common-mode, at least that's what PSpice says. I find that \$V_{DS}\$ of both MOSFETs is 1.1V and PSpice ...
4
votes
1answer
203 views

How do I appropriately power a headphone amplifier and where do I place the volume regulating potentiometers?

At the moment I am building a device that splits an analog stereo audio signal into 3 signals and amplifies 2 signals for headphones. I need to know how to supply -12VDC and where to put the volume ...
0
votes
1answer
40 views

2-stage BJT CC-EC amplifier [closed]

Using proteus I designed this amplifier: But I got this result: I don't know what is the problem in my design. I've been changing the values of the linking capacitors but didn't get any result.
0
votes
1answer
45 views

BJT LT spice DC transfer characteristic

Why is it that the DC transfer characteristic isn't flattening out at -5 v, so it looks like a Z-shape? I did a DC sweep from -10 V to +10 V. The input wave is a 2V sine wave for the graph below:
0
votes
1answer
59 views

Need help with three-stage transistor amplifier in LTSpice

I am currently attempting to design an amplifier in LTSpice for an E1 project. My professor tends to emphasize analysis of these circuits, so he hasn't really given us any kind of a design process to ...
0
votes
1answer
51 views

OP amp Comparator not working any tips?

I´m running out of ideas here. I have a device that should always output a 5v signal, with a maximum tolerance of 100 mV (4.95 to 5.05 V). I´m building a "tester" device. My tester will compare the ...
-2
votes
0answers
64 views

Not getting smooth sine wave on the output of the power audio amplifier

Power audio amplifier circuit not giving me an smooth sine wave output. Before iIadded the active bandpass filter I was getting smooth sine wave output with a current of 500 mA peak and 4V peak and ...
0
votes
0answers
57 views

Missing resistors vaules

A question for some guys is simple, but it is not for me. I am having difficulties finding the right formula to calculate resistors value or voltage drop across R1 through R8. Does anyone have an ...
-2
votes
1answer
32 views

Looking for a small comparators which do compare a input [closed]

and output when reach the set value。  Or can anyone tell a simple circuit to build one.
1
vote
2answers
73 views

Why my non-inverted amplifier does not work?

I'm trying to use a TL081, for which I used a DC power supply regulated by MPL1303, to feed the TL081 and a Vin from a DAQ assistant giving an analog signal of 0 to 5 V. I tested the signal from the ...
0
votes
1answer
70 views

Transistor current amplifier circuit

I'm trying to make a circuit that has a load resistance of 2 Ohms, load current draw of 2A and voltage of 5V. The circuit can only be fed with a 5V@500mAh battery. Here is a diagram I have thought ...
0
votes
1answer
27 views

Class a amplifier load capacitance

What would happen in a class a amplifier if I connect a capacitor in series with the load resistor (between power supply and the transistor collector)? My goal was to block the dc qiescent current to ...
1
vote
1answer
111 views

Op-amp problem, two inverting amplifiers?

So I stumbled across a rather strange ideal op-amp circuit that I've never encountered before. I've done enough problems regarding inverting amplifiers, non-inverting, summing, difference, and such, ...
0
votes
2answers
64 views

Current sense amplifier

I came across this circuit for a high-side current sense using BJT current mirror, and I am trying to derive a formula for how I could calculate the sense voltage output (going to the FB pin) in terms ...
0
votes
2answers
80 views

Is my amplifier correct?

My goal was to amplify audio signal coming from Raspberry PI's audio jack, so it is louder. I have basically no clue what I am doing, but it seems to work - when I connect the speaker directly to the ...
1
vote
0answers
23 views

Operation of Swing-Type Voltage Controlled Amplifier

I'm trying to understand this Swing-Type Voltage Controlled Amplifier which is found in the classic Roland TR-808 drum machine. What I understand currently is that the input signal to the base of the ...
0
votes
1answer
63 views

Class-AB Amplifier Excessive Heat

I'm using a TI TPA6017A2 as a pre-amp for an in-car audio application and it's getting excessively hot, to the point where the IC burns my finger when touched if I set the input volume to max. Beyond ...
0
votes
0answers
75 views

Extending the negative rail range for an Op Amp

I'm building a Transimpedance amplifier using the ADA4530-1 op amp by Analog Devices. I'm attempting to sense a fA current signal that is always negative and I would like to see if it would be ...
0
votes
2answers
55 views

Amplifier MOSFET (25m - 5V)

I dont know how to amplify a signal of 25mV to 5V amplitud signal ((frequency of audio input cell phone)). I have this circuit so far:
0
votes
2answers
73 views

Not getting an ac current output through my speaker in my amplifier circuit

Will the dc current output affect the speaker, and prevent it from functioning properly? I have already tried different capacitors also change the input voltages and frequencies. I would really ...
0
votes
1answer
124 views

when a diode is forwards biased can current flow backwards through it?

when a diode is forwards biased can current flow backwards through it? this question comes from me trying to understand class AB amplifier biasing, so any additional comments about the diodes' use ...
0
votes
0answers
33 views

How do I design a MOSFET based amplifier with constraints

I am designing an amplifier using two MOSFET stages. The input is taken from a sensor and is to be amplified by a factor of 25. The output (of these two transistors) will be fed to a detector with a ...
1
vote
1answer
29 views

Matching Networks on Narrowband Multistage Low Noise Amplifier (LNA)

How does the inter-stage matching network of a narrowband LNA compare to that of a wideband LNA for the same multistage design? I've read somewhere that narrowband LNA does not necessarily require a ...
2
votes
1answer
67 views

Reasoning behind values of CE amplifier

I have the following circuit: I am asked to choose values for the different components such that at the end, the amplifier meets certain requirements. In the solutions, I am told that to minimise ...
0
votes
3answers
129 views

Is a bigger resistor different from a smaller resistor with same color stripes?

I changed a resistor with same color stripes Yellow, Purple, Gold, Gold on a Pioneer surround system but the only difference was that the I put was a bit bigger. The problem is the system went into ...
0
votes
1answer
36 views

Cascading an Op Amp at a desired frequency question

So I have a lab practical with the instructions "Demonstrate an operational amplifier circuit which may consist of one or two op amps with a gain of X (±10%) and a -3dB frequency exceeding Y kHz. The ...
0
votes
0answers
22 views

Can I choose the 18W amp for my 1" tweeter (50 W AES Power Handling)

I have a question - I want to take a 18W TDA2030A amplifier kit to power my tweeter in my PA system. I have an active crossover in it, that's why I have separate amp for each driver. My tweeter is 1" ...
0
votes
0answers
60 views

LM386 and strange way of curbing noise

I am using an LM386 to drive a cheap 1-2 inch 8-ohm speaker. The input to the LM386 is an output from a DAC, which is outputting a sine wave between 100-1kHz, so I don't need any frequencies above ~...
1
vote
0answers
17 views

Common Source with Active Load

I'm trying to design this circuit using gm/Id method. I am already able to achieve the desired GBWP and Gain (this is just a simple example so I'm just trying to achieve both) but I'm having trouble ...
0
votes
1answer
68 views

How can I build BJT amplifier with Vin and Vout requirements (peak to peak values)

I have been working on a project but I'm not sure if I'm complying with the requirements that I was given. Design a BJT amplifier such that VIN=0.1 V and VOUT=5 V (peak to peak values). ...