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)

Filter by
Sorted by
Tagged with
1
vote
1answer
17 views

Implementing negative feedback on a JFET amplifier

I have started designing and simulating a simple Jfet amplifier using LTSpice. The circuit I have below seems fine, apart from too much gain for my needs (about 20x to much gain). To fix this, I ...
0
votes
0answers
12 views

CS Amplifier without load or signal resistance

So I came across this interesting MOSFET question and thought I'd give it a try. I seem to be stuck on a couple of parts however, hopefully someone can see something I'm not seeing. Here is the ...
1
vote
1answer
69 views

Help with understanding transistors in circuits

The picture above is a circuit for a hearing aid, so we need sound amplification. BC547 is NPN, BC557 is PNP. How is the amplification happening, why is it connected so?
0
votes
0answers
35 views

How would I find the gain equation for this circuit?

I can neglect the Early Effect for the BJT, and assume the capacitance is infinite. Using the small-signal AC model, I calculated $$r_e = 25 \Omega$$. My question is, how do I set up my equations/...
0
votes
1answer
59 views

What will be the Gain if the resistor value tends to infinity? [closed]

Given the circuit above, I need to find the expression for gain if the r_pi tends to infinity. my question is will v_pi still be v_in?
0
votes
0answers
43 views

Analogue signal issue?

I have an issue with a analogue signal. Your help would be greatly appreciated. The signal is a 5Vdc, it is an output from a PCB which is a source to many A/D PCB. its output is connected using wire ...
0
votes
1answer
64 views

How do I calculate the wattage of a set of speakers?

I've just received a set of speakers that I want to design an amplifier for. Two of them are 5W 4Ω and one of them is 10W 8Ω. How do I find the total peak power output of these? I apologize for such ...
-3
votes
0answers
39 views

What is the difference between these CE amplifiers? (Why we use op-amp in this CE amplifier circuit?) [closed]

Above image is Common Emitter Amplifier - (Circuit 1). And above image is another Common Emitter Amplifier using operational amplifier (op-amp) - (Circuit 2). This image is Simulation Result of ...
1
vote
2answers
72 views

Misunderstanding of calculating gain of amplifier

I’ve been reading in my textbook that the gain is Gain= Vout/Vin= 1+ Rf/Rin However, what if there isn’t a resistor like this amplifier? Would it be 1V/V or 2V/V? Or am I totally misunderstanding this?...
0
votes
1answer
47 views

Problem in microphone circuit

I've placed the circuit on the breadboard and found an unexpected low-frequency noise appearing again and again. The computer microphone doesn't show this type of distortion. But my circuit is showing....
0
votes
2answers
50 views

Piezo signal amplifier using LM358 opamp

I was trying to amplify the signal of a piezo, which is very low and amplify it so that I could use it to latch a flipflop. I had the LM358 opamp so I made a differential amplifier by a gain of 50 so ...
0
votes
3answers
42 views

Would we like to have a linear circuit application to cause low distortion at the output port?

Would we like to have a linear circuit application to cause low distortion at the output port? What about a power amplifier? Is it necessary for a power amplifier to have only low distortion at the ...
0
votes
1answer
53 views

I want to understand this audio input to LED output simple circuit

I'm a newbie in electronics. I watched a youtube video that showed how to activate LEDs using a microphone. It's project #3 at https://youtu.be/zsJ61yJhWVU?t=115 The guy built the circuit on camera ...
0
votes
1answer
58 views

Circuit voltage / amp calculation

I am new to electronics (using Arduino), begging to venture into creating my own circuits and not following set example. I would appreciate advice on the following. When deciding upon how to power a ...
0
votes
1answer
59 views

How does the Common Emitter amplifier ensure low distortion?

My understanding of a small-signal amplifier is very limited. From what i've understood from this article is that for a BJT in the CE configuration, it provides minimal distortion at the output, I ...
0
votes
0answers
44 views

How to improve emitter-follower efficiency?

I’m trying to wrap my head around the emitter follower. I’m currently using it to simulate a ~12V AC coming from a intercom ringer (about 700Hz). simulate this circuit – Schematic created using ...
1
vote
2answers
35 views

Amplifiying PWM signal to 10v analog

I have a 5V PWM signal around 500Hz. I want to have 0-10V analog output from this. I considered using a MOSFET to step the 5V PWM to 10V PWM and using a low pass filter at the output to achieve my ...
1
vote
2answers
90 views

How is this pole compensated

I have an amplifier in a closed loop, the diagram looks as follows: The DC gain is simple which \$ -Rf/R1 \$. If I make \$ -Rf=2\cdot R1 \$ the the DC gain is two. This is verified using AC analysis ...
2
votes
0answers
52 views

Voltage-divider bias common emitter calculations are yielding unexpected results

I performed an analysis on this voltage-divider-feedback common emitter. My result in simulation is relatively close, but doesn't quite check out. Where did I go wrong? I'm new to this and ...
0
votes
1answer
55 views

Purpose of resistor in pre_amp circuit

Trying to understand this circuit. What is the resistor R1 for? Wouldn't it just continuously supply voltage to the base and make it always "ON"? Another version:
5
votes
3answers
453 views

Cascading common emitter and common collector

I am trying to design an amplifier for a 1 W 8 ohm speaker for educational purposes. The idea is to start from a common emitter amplifier to amplify voltage and then add a common collector (emitter ...
2
votes
0answers
67 views

How do I perform ac analysis of common emitter with voltage divider feedback?

I'm working towards understanding voltage-shunt feedback. I'm about halfway there, and stuck. I am building a simple common emitter with voltage divider feedback. I managed to get it biased to put ...
1
vote
0answers
37 views

Location of Amplifier for Signal Integrity

Let's say I have a photodiode that outputs a current with respect to incident light on the die. If this photodiode will be located 12 inches or so away from the control board, would it be better for ...
0
votes
2answers
95 views

Trying to obtain a voltage gain equal to 3 without an op-amp

I'm a beginner in electronics and currently, I am trying to design a Wien bridge oscillator. I've read documents about oscillators. For now I am stuck at trying to design the amplifier, without using ...
0
votes
0answers
24 views

How can I get rid of the noise from this audio amplifier (using a Kemo M031N)?

I am trying to wire up an audio amplifier circuit using the Kemo M031N 3.5W amplifier: I have connected the wires from the amplifier to a terminal block. With a suitable 10V power supply and a 2W ...
1
vote
0answers
46 views

How to connect a load to an amplifier without a loss in gain?

I have this circuit below, that represents a common emitter amplifier: When connecting a load of 10 ohms to the collector node and a signal to the base node there is a huge loss in the gain of the ...
0
votes
0answers
33 views

Effects of bootlace ferrules to connect load-cell with amplifier

My colleague and I had an argument about whether or not to use bootlace ferrules for a load-cell (4 stranded wires + 1 shield | 100mg precision | OIML C3 | max. 3kg) going into an amplifier (spring-...
3
votes
1answer
109 views

NUCLEO-G031K8 ADC conversion for audio recording — bit resolution and recording quality

I am planning to use NUCLEO-G031K8 board as an audio interface for my electric guitar to computer. So I designed a circuit to amplify small signal of guitar. When I check board's datasheet it is ...
2
votes
0answers
27 views

How do you find rO when solving this differential amplifier?

gm could be determined using Jacoletto (40*Ic, where Ic was found while solving the bias point)? Some of my attempts at solving the circuit
0
votes
0answers
44 views

What unit is expressing the effect of this capacitor in a common emitter amplifier?

I'm working through this handout I3.PDF in my attempt to understand negative feedback in amplifiers. The following formula appears, in which the author is substituting \$v_{out}\$ and \$v_{in}\$ to ...
0
votes
1answer
23 views

Stability analysis of cross-coupled amplifier in Cadence

I am trying to implement a cross coupled amplifier with OP-AMP feedback. I am not able to get it stable for a square wave however. The circuit looks as follows: The OP AMP is ideal from Cadence, all ...
0
votes
1answer
42 views

I designed a 4 Resistance biased amplifer, I used the Voltage divider MOSFET amplifer circuit for 2N7000

The blue lines in the simulation are the output and the green lines are the input, So I designed this amplifier while trying to limit Id to 200mA and I wanted to Bias the MOSFET such that I get no ...
1
vote
1answer
92 views

I am designing a 2 resistor MOSFET amplifier but the output is generating square waves

I am learning about MOSFETs and I was tasked to design a 2 resistor biased amplifier. This is what I came up with. I am really not sure what a 2 resistor biased amplifier is, could someone please help ...
0
votes
1answer
58 views

How do I compute the gain on this differential amplifier (in an open loop)?

Hello! I've got this project due for a college course, and the teacher has reviewed my work and said that it is within specification, but he asked me to compute the gain the good old fashioned way ...
0
votes
0answers
74 views

Audio jack acts like an antenna?

I am using a simple pre-amplifier circuit for an electret microphone. Here's the schematic and the AC transfer function: The output is connected to a 3.5mm audio jack through a couple of half a meter ...
0
votes
1answer
57 views

Calibration of response of A preamplifier : LTSpice

I would like to calibrate my electronics. Row signal is something like pulse-A, width is 40nsec. When I input this signal to preamplifier, output is something like pulse-B. I would like to calibrate ...
4
votes
2answers
102 views

Homemade GPS Receiver: Cascading LNAs and Band-Pass Filters?

Over the last couple of months, I developed a software-defined GPS receiver. Unfortunately, it's not very sensitive, and can only detect very strong satellite signals. For the RF front-end, I am using ...
0
votes
2answers
103 views

Upper 3-dB frequency of differential amplifier with current mirror load vs with resistive load

In the BJT case, why is it that the upper 3-dB frequency of a differential amplifier with a current-mirror load (1st picture) is lower than that of a differential amplifier with a purely resistive ...
0
votes
0answers
54 views

Pre-amplifier gain issues

I built a 2.1 subwoofer circuit. The schematic is below. The problem is the sound is low volume. It should be louder than this. I want to confirm the coupling capacitor values are ok in every ...
0
votes
0answers
19 views

Strain gauge measurements with carrier frequency

In near future, I would need to do strain gauge measurements using HBMs instruments, the amplifier will be MX1615B. In my case, the gauges will be placed near a 50Hz gearmotor and run with VFD. As far ...
1
vote
1answer
53 views

Measuring RMS power output from audio amplifier channel

I am looking for a simple way for getting the RMS power output of an amplifier channel set to some arbitrary gain. I want this in order to find the maximum level I can safely set the amplifier at for ...
0
votes
0answers
39 views

Question about local NFB in a transistor

I've seen this a few times and I can't seem to find documentation so maybe I'm not understanding what's happening here. My interpretation is that the transistor is configured as a common emitter and ...
1
vote
1answer
44 views

Long-tailed pair LTspice simulation

I have been having some trouble designing a long-tailed pair transistor amplifier. Vdd2 is 5V and the 6.8k ohm resistors were already given. I am trying to get a bias voltage of 0.8V at the transistor ...
1
vote
0answers
38 views

Voltage gain of BJT CE stage amplifier

The question is to calculate the voltage gain, V_out / V_in in terms of small signal parameters and R_C. (Ignore Early effect) First I made a small signal circuit for it, and found voltage gain. But ...
0
votes
0answers
24 views

Lock-in sensitivity and output signal

I am measuring a signal with a lock-in amplifier (SR830) and sending this signal through a GPIB connection to a LabView VI. Should there be a coefficient on the voltage I receive in my VI to read the ...
0
votes
0answers
26 views

Need Help with the transistor configuration? Biasing methodology used in circuit?

I am confused about how this circuit works, the circuit is the instrumentation for IR sensor even I have never encountered the such biasing, the IR led is activated with the pulse of 150 us the output ...
0
votes
1answer
45 views

Identifying bjt amplifier circuits configurations

how to identify configuration (CE or CB or EF) of this bjt amplifier circuit ? in complex circuits (bjt amplifier), most of the times I have this problem of figuring out its configuration. My ...
0
votes
1answer
35 views

LM386 LTSpice simulation output problem

Source I am trying to simulate this circuit before setting it up on breadboard. I have downloaded this model for simulation. And set up the circuit. After transient simulation what I get from vout: ...
0
votes
1answer
50 views

Kirchoffs Laws and Class-A Amplifier Circuit

I have been attemtping to use Kirchoffs laws to solve a Class A amplifier circuit containing a single transistor. I made several attempts at this trying slightly different approaches. I summarized the ...
1
vote
2answers
64 views

Why input impedence is important factor for amplifiers

What I know about amplifiers is that its main objective is to amplify small ac signals and how much signal can be amplified is known by calculating open circuit output voltage (without load) or more ...

1
2 3 4 5
74