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)

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33 views

Multistage Amplifier Design using differential amplifier

I am a freshman in ECE major and try to design a multistage amplifier. The requirements are: Rs = 100 kΩ RL = 10 kΩ CL = 47 pF PMAX = 5 mW gain must be at least 50 Here is what I design. I am ...
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1answer
39 views

Finding Loop Gain (Aβ) of Transimpedance Amplifier

I have been having trouble finding the loop gain (Aβ) of the following transimpedance amplifier: simulate this circuit – Schematic created using CircuitLab To find Aβ, the books I have ...
3
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2answers
48 views

Must both transistors in a class AB amplifier push-pull pair need to be matched?

A in push pull pair the emitter of the two transistors are connected together. Therefore, what difference would it make if they are not matched vs if they are matched i.e they have same beta value.
3
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1answer
86 views

Non-inverting and inverting gain of differential amplifier

simulate this circuit – Schematic created using CircuitLab From what I understand, the diagram above is of a differential amplifier and I understand them and how they work. But the ...
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1answer
72 views

plugged 240v into 110v amplifer - is this repairable? [closed]

I imported a 200w mono subwoofer amplifer from the US and stupidly misread the 250v fuse rating as the input voltage. Plugged it in into my UK 240v supply and the slow-blow fuse blew. I have since ...
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1answer
39 views

Amplitude modulation and heterodyning [on hold]

I can't seem to find a difference between the two, can someone please explain if there is any? thank you
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0answers
15 views

How to work out (Hie) input impedance for ZTX650 BJT Transistor?

Please can someone tell me how I can work out hie (COMMON EMMITTER MODE) for ZTX650 BJT Transistor. It is not anywhere on the data sheet. From all the research I have done, one website has told me hie ...
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0answers
67 views

voltage amplifier stage for audio

Are there any blaring reasons for why this voltage gain stage wouldn't work? Or anything that can obviously be improved upon? I don't currently have a current mirror to bias the bases of the voltage ...
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1answer
33 views

Audio Amplifier Design (CE Amplifier - Class AB Power Amplifier)

I am trying to design a Audio Amplifier which provides a gain of 20db (10V/V). I have managed to design the following circuit but the output voltage gets clipped and clamped. Please find the schematic ...
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2answers
33 views

CE Amplifier Design for Audio Amplifier

I am trying to design an audio amplifier which provides a maximum gain of 20dB (or) 10V/V . For the circuit I designed the lower half of the amplified signal is being clipped. I am also attaching the ...
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0answers
26 views

Amplifier Schematic Question

I have acquired two Hitachi ss-81A (not my post, but same speaker model) and I want to build an amplifier for them. They are 8 ohm, 4 watt max speakers. From my research so far, it seems like the ...
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0answers
45 views

How to design a BJT amplifer with a gain of exact 100? [closed]

How to design a simple BJT amplifer with a gain of exact 100?
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1answer
23 views

How to work out (Hfe) AC Forward current transfer ratio for ZTX650 BJT Transistor?

Please can someone suggest to me how to work out the AC Forward current transfer ratio for this BJT Transistor (ZTX650 BJT Transistor) used in common emitter. I looked on the data sheet (herewith is ...
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2answers
113 views

Question about amplifier design

I'm somewhat new to analog circuit design, and I have some questions about this circuit, which I came up with trying to understand how transistor amplifiers work: simulate this circuit – ...
2
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1answer
88 views

is this how we select a transimpedance amplifier for photodiode applications?

before entering in to problem: my application is a laser pulse detection, in this process when a laser pulse falls on photo diode it generates current, for which i need a Trans Impedance Amplifier ...
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0answers
51 views

Design of a two stage BJT amplifier (CE-CC) [closed]

Hi guys, I need to design a circuit and find the values of the components. There are 2 ZTX650 npn bjts. It has to be designed for an 8 ohm load which has to be driven with an output signal of 1 v ...
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0answers
32 views

choosing a high speed analog multiplier [closed]

I am interested in a simple squaring/sqrting analog circuit for high frequencies, from about 500 MHz to >1 GHz. The lower frequency multipliers e.g. AD 734 are easier to use, but the faster ones are ...
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0answers
47 views

What is the coupling coeffecient of a 10.7Mhz if transformer?

Does anyone have a rough range? I just need to be in the ball park. As an experiment, I'm simulating some if amp circuits in LTspice and it looks like they are very overcoupled when using a coupling ...
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0answers
14 views

ACPL-C79B problem

This is my first post on this forum. I have a problem with an isolation amplifier and i hope there's someone here who can help me out. Let me explain my situation. I use an ACPL-C79B from Avago to ...
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2answers
61 views

can i use dual supply op amp in single supply mode?

Can i use dual supply op amp in single supply mode? Is it okay to convert a bipolar voltage to uni polar and then feed it to a single supply op amp(amplifier)?
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2answers
37 views

How to find value of beta = (mu*Cox)(W/L)/2 of MOSFET in ngspice

How to find value of \$\beta = \frac 1 2 \mu \cdot Cox \cdot \frac W L\$ of MOSFET in ngspice? Is there any command that displays that? The 'show' command displays many parameters but it doesn't ...
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0answers
33 views

Amp troubleshooting with clicking relais

Im having some trouble with my old Realistic amplifier. Out of nothing, my speakers started to make a repetitive (about once a second) full in and out movement of the cone, producing a deep bass ...
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2answers
73 views

Darlington-pair transistor power amplifier for cd-player

I want to build simple one-transistor power amplifier for cd-player. I found 2sd605 Darlington transistor for it. I use 8 Ohm load speaker and have a lab power supply 20V. I want to connect speaker ...
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1answer
40 views

pwm amplifier with npn bjt

I'm trying to do a pwm amplifier in order to control 3 fans with one pwm signal. Since there are three fans and according to the pwm specs allowed current per each is 5-8mA, I expect current load of ...
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0answers
6 views

Arduino continually resets when connected to external power supply, but not USB [migrated]

I'm working on a seemingly simple Arduino project which plays a sound and flashes an LED when provoked by some trigger. The problem: When powered by an external power supply, the Arduino continually ...
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2answers
50 views

Distortion in TDA2030 circuit

I looked at a friend's guitar amplifier which wasn't working, the problem was clearly (because it fell off) a broken IC (TDA2030AC). After replacing it, the amplifier started working again but when I ...
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2answers
83 views

I need some help with analysing this differential amp

I'm having some trouble with analysing a differential amp. The amp and its associated operating parameters are in this link (question 1) http://imgur.com/iS6fD5N What have I done so far? Well I've ...
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0answers
43 views

Why is the dependent current source ignored?

I need to find i1 / v1 when i2 = 0. According to the solution manual, the KVL is -V1 = 2kOhms*i1 + 1kOhms(i1 + i2), and since i2 = 0 they get -V1 = 3000i2. Are they forgetting the dependent ...
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4answers
65 views

Common Mode Gain BJT Differential Amp

I'm trying to determine the common mode gain and differential mode gain of the follow amplifier. Now I understand what the common mode voltage and differential mode voltages are, but I'm unclear as ...
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4answers
101 views

How to design Current Amplifier circuit to amplify the signal current to 1A

I am trying to design a current amplifier circuit to amplify a signal current to 1A. Application : I am generating a signal using microcontroller (for ex : Pic16f877A). This signal is 5v having 10mA ...
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0answers
19 views

circuit/multisim troubleshooting

I can't seem to get an output wave to appear. Can anyone see anything wrong? Or are my values off, like the capacitors?
0
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1answer
60 views

op amp oscillation problem during chip measurement

I had an oscillation problem when testing my fabricated chip. As shown in these figures, the transient waveforms of the op amp outputs got severe oscillations. Ch1 and Ch2 are the two output nodes and ...
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1answer
76 views

Voltage drop at input of opamp

simulate this circuit – Schematic created using CircuitLab At VM1 I theoretically expect about 1mV. When I connect with the opamp I get a voltage drop of 0.5mV at VM1, I get this values ...
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19 views

Impedance in ideal electronic components [duplicate]

Why is it desirable to have Infinite input impedance and zero output impedance in electronic components? I thought of this question while studying the characteristics of an ideal OpAmp.
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3answers
507 views

How to convert 14V AC to 5V DC?

My interphone's buzzer receives an AC voltage of 12V. I would like to substitute this buzzer with an embedded board (raspberry-pi). What would be the ideal way of converting such voltage to 5V DC? ...
0
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2answers
29 views

Transimpedance amplifier with current amplifier circuit.

Figure shown above is the current amplifier circuit with the output current feeding into the transimpedance amplifier (I-V amplifier). I'm using a 100mV ac signal and 120 Kohm resistor to produce a ...
0
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1answer
60 views

How do I get rid of speaker static?

I made the basic TPA1517 circuit as shown on page 11 of the datasheet. When there is nothing plugged into the input, there is a lot of static. When I do plug something in, there is less static, but it ...
1
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0answers
36 views

How does a cascode or beta-enhanced voltage amplification stage work?

I'm studying electrical engineering and we just finished a project where we had to build a power amplifier. But I think I can do better than what we did. I read Distortion In Power Amplifiers where ...
3
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3answers
70 views

Is a mosfet considered as a transconductance amplifer?

Is a mosfet considered as a transconductance amplifer because it converters input voltage into output current?
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1answer
27 views

Can I connect an amplifier to a Crystal Radio?

I am wanting to create a crystal radio that connects to my amplifier (It is for a guitar and has 3.5mm and 1/4" jacks). The diagram is as shown: Would this be possible and work? If not, please ...
0
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1answer
35 views

Getting rid of electrical noise produced when one touches amplifier and amplifier's dials

I purchased a Lepai LP-2020A+, which is a pretty good little amp for the price, but I've modified it to make it much better and decided it deserved a better casing to look the part, too. So I ...
2
votes
2answers
127 views

Boost the signal of an FM transmitter using an “emitter follower” transistor [closed]

EDIT: I've seen an alert under my question: “Please clarify your specific problem or add additional details to highlight exactly what you need. “ Maybe this is due to the fact that I'm not very good ...
0
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1answer
47 views

Could anyone explain why differential biasing is easier than single-ended one? [closed]

The lecture says that differenial biasing is easier than single ended. Could anyone explain why differential biasing is easier than single-ended one?
3
votes
1answer
32 views

What does an impedance to a fixed potential mean?

I am reviewing about differential pair and this comes up a bit confusing. Could anyone explain the part "equal impedances to a fixed potential" here? What does an impedance to a fixed potential mean? ...
0
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1answer
35 views

Class B Push-Pull Amplifier

This is the circuit Can you please explain how did obtain the AC equivalent circuit
0
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1answer
55 views

Input resistance of differential LNA

This is a wideband differential LNA. I am trying to calculate the input resistance of this circuit but the result is not anything similar to the result shown in the picture below. Could you explain ...
0
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2answers
63 views

Multi-stage differential amplifier

What is the purpose of combining two differential amplifiers as in the figure below? The first differential amplifier is a single input balanced output and the second differential amplifier is a dual ...
0
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0answers
34 views

Effects of introducing offset in a current sense amplifier

I am working with the MAX9643 current sense amplifier in a configuration similar to this. I need to introduce a small offset in the output voltage. What are my options of doing this? Can I directly ...
0
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0answers
27 views

Transformer Coupled Push Pull Amplifier Class B

Can somebody explain why do we to have the Vcc,R1,R2 or biasing network at the first transformer Ve of the transistors are grounded , so I'm guessing it that the forward voltage Vbe = Vb - Ve = Vb ...
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0answers
35 views

voltage drop when probing a NPN transistor's emitter to collector, collector to emitter for PNP

I have some old 2SD1785 and 2SB1258, NPN and PNP transistors that I pulled off of a car audio amplifier. Using this site, I tested the transistors in question and find that they fail on the test on ...