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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11 views

Remove mains hum out of amplifier

I have a headphone amplifier that is afflicted by mains hum 60 Hz and upper harmonics, below is an FFT of the spectrum with nothing connected to its inputs. In headphones you can clearly hear a ...
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1answer
66 views

INA155 reference pin not working

To test the INA 155 I gave a sine wave of amplitude 0.2 V p-p 100Hz. It was operated at 5 V single supply. The reference pin was connected to 2.5 V from an op amp buffer. There seems to be no offset ...
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2answers
55 views

Single double triode vacuum tube for headphone amp at high voltages

I'm planning to build a single double triode vacuum tube as I have seen many schematics even though most of them are low voltage (20-40v). However I didn't seem to find a high voltage single double ...
3
votes
2answers
71 views

What is a PA/LNA?

I saw a comparison of two similar radio receiver modules. They used the same IC, but one had a greater range due to the inclusion of a "PA/LNA" which I understand to be an abbreviation for "Power Amp ...
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2answers
61 views

Calculating the Gain in an Amplifier circuit

Having some issues calculating the gain in circuit below, it is apparently 1802, but I can't seem to arrive at this answer. If anyone could help explain how to get this answer I'd be very ...
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2answers
58 views

Unexpected results when trying to amplify voltage across a wheatstone bridge

I am working on a project, and am trying to amplify the voltage across wheatstone bridge. Here is the diagram: where \$R_1 = 1,000 \Omega\$ \$R_3 = 10,000 \Omega\$ and \$R_2\$ is a ...
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0answers
33 views

SOS! Finding Open loop gain - breaking feedback loop

I’ve just become quite confused regarding on how to break the loop; please can you clarify if there may have been a mistake in one of the solutions to part d) of this question where it it is required ...
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1answer
39 views

Calculation of Breakdown Voltage

How can we calculate the breakdown voltage of a BJT in ADS? Is it Possible or not in ADS? Problem:- I have a ADS BJT model. I am using that to generate high voltage output. For that i need to bias ...
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1answer
312 views

Identifying this "IC”, Trying to reverse engineer a board

Part 1: the board and how it's connected I'm looking at a headphone sound amplifier that is used to help experts detect pests in palm trees when a microphone is placed on the trunk of the palm tree. ...
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2answers
74 views

what is the maximum output voltage from an opamp in general case?

In general, what is the output voltage that an amplifier (not rail-to-rail output type) can provide,if it is supplied for example Vdd=+24V and Vee=-24V which is the maximum value I can get "for sure" ...
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1answer
40 views

What sort of problems would I face using computer speakers for dramatic sound effects? [closed]

I am building a dramatic space (like a haunted house.) I would like to play several different sound effects in several different places at different times. I am considering mounting several computer ...
1
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3answers
53 views

How to remove noise from power adapter

I am making an audio amplifier using an LM2879. I am using the schematic provided in the data sheet. For a starting point, this design works pretty well, although the base cutoff point could be a ...
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1answer
28 views

Calculate the parallel value of resistors at base of common emitter amplifier

I don't know if questions can be asked like this here but if they can I want this question. In an exam paper I saw a question to determine the parallel value of the R1 and R2 resistors in the image ...
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3answers
60 views

Gain vs Output Impedence

I am currently trying to improve my understanding of analogue IC design and my textbook kind of brushes over this problem. It is made quite clear that a low output impedance is desired so that the ...
1
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1answer
66 views

How many stages of transistor amplifiers should be used in order to produce an audible output

I have constructed this amplifier as shown in the circuit diagram: simulate this circuit – Schematic created using CircuitLab I have made a few inferences: Reducing the value of ...
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0answers
24 views

Proper Capacitor for 555 Circuit with Simple NPN Amplifier

As I understand it, in the classic 555 with a speaker circuit, the capacitor that is in series with the speaker is there to prevent DC from flowing through the speaker: And this capacitor, C1, is ...
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4answers
142 views

What does a transistor amplify?

hi guys it’s been days i am searching and reading articles and books to find out what is the factor that a transistor amplify? which leg of transistor does provides this amplified factor? i know ...
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1answer
33 views

Turn on 12v car amplifier with ATX POWER_GOOD?

Does anyone know how to turn on a 12v subwoofer amplifier, using the ATX power supply control wire for POWER_GOOD? I am using an Azza model PSAZ-1000A14S, 1000 watt, single 12v rail, computer power ...
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2answers
54 views

Amplifiers: Periodic and non-periodic signals

All the signal amplifiers (op amps) I've dealt with thus far use periodic signals. The idea of bandwidth is natural when dealing with these periodic signals because it is just a description of the ...
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17 views

Small circuit analysis on Common Emitter with bypass capacitor

I'm really not sure how to approach the C2 capacitor in this case, I'm sure it's easier than it seems! I'm not sure about how C2 would affect R5 when performing small signal analysis, would R5 ...
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1answer
104 views

Old radio amplifier circuit explanation

could somebody explain me how does this audio amplifier circuit from old radio is working ? I understand role of last transistors 413,417 and 415,419 but what is the point of T409 and T411 and other ...
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1answer
31 views

Lock-in amplifier output to spectrum analyzer

In several lock-in amp tutorials and experiments (including at the end of “Physics 111: Low Light Signal Measurements” on Youtube), the lock-in amp X or Y output is applied directly to a spectrum ...
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1answer
31 views

Design of the two stage amplifier with p-type input

I have to design the two stage amplifier with p-type input (p-type diff pair), the schematic bellow: However, mostly tutorials discuss the same architecture but with n-type input. My main ...
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1answer
39 views

Resistance measurement using high side current sense amplifier

I want to measure very small resistances (0.5 to 1 Ohm) using a high side current sense amplifier. The device I have in mind is MAX9611. The typical application circuit from datasheet is like: My ...
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2answers
58 views

How to supply power to INA128 amplifier

I'm trying to amplify an EMG signal from two electrodes with a INA128. However, I'm not sure how to connect the power supplies. I'm taking the 12V from the wall and using a voltage divider to get +6V ...
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1answer
34 views

How do I check my Electret mic?

I recently soldered an electret mic. I have never soldered before. How do I check whether I have damaged the electret mic? If it was a speaker I could have done continuity check but for a mic I don't ...
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4answers
100 views

Where does an op amp's input bias current come from if capacitor is used?

In the case of a non-inverting amplifier, if I DC couple the input signal with a capacitor only, \$C_1\$ (i.e. no resistor to ground), sources (as well as an experiment in the lab) show me that the op ...
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1answer
27 views

Analog circuit design(amplifier with BJT) with abstraction(model)

I tried to cascade two circuit consisting of BJT transistor : Common Emitter stage, Emitter follower. I do abstraction like belows, which means you just need to know only each unit block one by one ...
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0answers
24 views

Low pass filter for differential signals

I'm building an adc and amplifier circuit for sensing a differential signal out of a pressure sensor. My plan is to use a circuit very similar to what is seen below: The total differential output ...
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2answers
72 views

Operational amplifier parameters: Input bias current, Input offset current, input offset voltage

I've been reading about input offset voltage, bias current, and current offset for a few days now and still can't get some things straight. I'll summarize what I understand and then pose the ...
6
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4answers
561 views

What parameters of a real op amp determine the lowest voltage it can amplify?

I am trying to amplify a 0.5mV AC signal (from around 4kHz-8kHz, generated by an electret microphone) to about 50mV. I am thinking of using an inverting amplifier using LM358 op-amp. The datasheet ...
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0answers
19 views

difference between numerically and parametrically

I'm calculating DC gain in differential amplifier. The questions say the calculations can be done both numerically and parametrically. I couldn't understand the difference between the two. I just ...
6
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2answers
88 views

What is the output impedance of HF power amplifiers?

In case it matters, let's discuss solid-state, linear, class AB amplifiers operating below 50 MHz and on the order of 100 W. Here's my confusion: I'd think ideally, the output impedance of the ...
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22 views

Phase shift introduced by OpAmp with high-pass filter on the non-inverting pin

I would find the phase shift between the signal S1 and the output signal of the first OpAmp TL081. I have considered that the signal S1 is modified by the high pass filter (composed by the resistor ...
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1answer
42 views

Transistor Differential Amplifier Non-linearity

In The Art of Electronics 3rd Edition, the authors comment on how the grounded-emitter amplifier has a highly non-linear response, because the gain is related to the intrinsic emitter resistance ...
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2answers
42 views

Input impedance of audio amplifier, unclear from datasheet

I have a AN7190NK audio power IC. It is a amplifier for the car radio. I want to know it's input impedance. In datasheet it states that: Input impedance ZI VIN = ± 0.3 VDC 28 kOhm I don't really ...
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1answer
47 views

How to get current to the load with a buffer Op Amp

I am reading about voltage buffer Op Amp configurations and it seems like there is no current through the circuit, specifically the load. So why would you want to get a specific voltage to the load if ...
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1answer
79 views

BJT Common Emitter Positive Power Gain [closed]

I am trying to complete a simple amplifier project using a single transistor common emitter amplifier. I understand that the common emitter is inverting but I need the power gain to be positive. The ...
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1answer
35 views

generating a 10mVpp signal from computer

I have an input to a system that requires a 10mVpp max signal. I have to use my computer to input it due to constraints out of my control. I am well aware an audio card cannot go down that low. I ...
1
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1answer
32 views

Significance of Linearity in RF Power Amplifiers

I have started studying the topic of "RF" Power Amplifier (PA) operation, and so far I have come across description like, if PAs are non-linear, it does not form a straight line and rather it has a ...
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0answers
47 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 ...
0
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1answer
51 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
votes
2answers
63 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
98 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 ...
0
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1answer
78 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 ...
0
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0answers
18 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 ...
0
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1answer
46 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
37 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
30 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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1answer
30 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 ...