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
1answer
45 views

Choosing transistor for amplifier

I'm going to design amplifier, requirement is that impedance for in should be more than 20kohm, impedance for out should be less than 50ohm, and voltage gain should be more than 200. So I'll make cc-...
-1
votes
0answers
16 views

Created this Filter Amplifier Circuit; How do I connect this load while maximizing gain?

*Filter Circuit on Left, Load on Right. To give some background, that load is supposed to replicate a long 12V power line (with other stuff on it) on which we will be sending AC signals on. The gain ...
1
vote
1answer
52 views

Buffer with TL084CN and resistors

simulate this circuit – Schematic created using CircuitLab There are two buffers made with the TL084CN, which is part of the conditioning of an LTS25-P transformer. Currently, I have put a ...
0
votes
2answers
55 views

Adjusting the voltage for a small speaker

I have a 4Ω 3W speaker and I plan to use it with MAX98357A amplifier. I need to make sure the speaker receives optimal voltage. When I test the voltage output from the amp playing nothing, I get 2.5V. ...
1
vote
2answers
63 views

How to decide bypass emitter resistance value?

This is an amplifier which has voltage gain of 50, quiescent current 1 mA and the input is signals from 20 Hz to 20 kHz. I calculated the collector current which is 1 mA, using that I calculated ...
0
votes
2answers
111 views

Amplify my 3.3V DAC signal to 220V

In one of my projects I need to generate different kind of 220V amplitude waveform signals in order to send commands to a heater using the pilot wire protocol. Here are the needed waveforms: Is there ...
0
votes
1answer
58 views

How do I remove the offset from the DAC output and change the range?

This DAC has an output range of 1-3 volts. Here's the datasheet: Datasheet I'm getting pulses with different amplitudes, frequencies, duty cycles and widths varying from 0.2 ms to 2 s from the DAC. ...
1
vote
2answers
98 views

Why high quality broadcast studio monitors use a middle range AB amplifier?

I had an issue with my Genelec 8010A studio monitors. Until recently I was truly happy with these monitors. The sound quality is exceptional, pure, precise the dynamic is impressive even though you ...
0
votes
1answer
56 views

Can't reach desired voltage on opamp output

I have tried to make signal amplifier just to gain some op-amps knowledge, but unfortunately it doesn't work. It simply doesn't reach desired voltage (set by resistors). I have used my old cellphone ...
0
votes
3answers
582 views

This is not my circuit, but anyway, What are they?

Hello. This is not my circuit, but I found it on Google. I'm just a newbie student, so I have two questions. Please, help me. (I started studying electronic circuit last week) 1) The meaning of ...
0
votes
1answer
62 views

Commercial broadband RF amplifiers

In the process of designing a broadband RF amplifier, I've come across some commercial boards, claiming gain flatnesses of +-1db from DC to 1Ghz. Those boards are ridiculously simple, having only one ...
1
vote
2answers
74 views

Extension of Audio Amplifier's Bandwidth

I am curious, whether extending audio amplifier's BW (bandwidth) beyond 20 kHz has any benefits compared to 2Hz-20kHz audio BW amplifier? Some say that high-frequency -3dB point should should be ...
0
votes
2answers
59 views

What is the purpose of \$C_E\$ in this circuit?

I understand it acts like a filter for \$R_E\$, but what is the point?
1
vote
0answers
54 views

Identifying Noise in 12AU7 Based Headphone Amplifier

I've been working on making a tube based headphone amplifier as a fun personal project. The amplifier is based around this 12AU7 vacuum tube. The project for the most part is following this existing ...
4
votes
4answers
591 views

High resolution ADC vs amplifiers

I have started a design for work where I want to interface some sensors, (strain gauge, bridge, thermocouple, low voltage stuff) to a national instruments sbRIO card. This card has analog inputs built ...
0
votes
1answer
38 views

Voltage drift in lock in amplifier

I am testing out the lock in amplifier with just a single resistor, but there seems to be a downward drift in the in phase voltage. What could possibly cause this to happen? Could it be some grounding ...
0
votes
1answer
43 views

Measurement isolated loop with Op Amp

I'm trying to measure a voltage across an Rsense (R2) in a galvanic isolated loop that flows a current (4 - 20mA). My Op Amp has Vcm +20V. But I'm worried about the voltage in nodes B and A with ...
3
votes
1answer
134 views

Reducing effect of MOSFET parasitic capacitance with resistor in series with gate

I have a MOSFET in series with the output of my amplifier to switch the amplifier output to the downstream circuitry. The MOSFET parasitic capacitance is seen as a load capacitance by my amplifier, ...
1
vote
2answers
107 views

Common emitter amplifier gain with load resistor?

I have a problem I am working on where I have to find the voltage gain of the following circuit with a dc collector current of 0.3mA. My attempt at a solution involved using the formula A=-(RcIc)/Vt ...
3
votes
1answer
75 views

Calculating grounded emitter amplifer distortion (Art of Electronics 3rd Ed.)

Referring to section 2.3.4 A1 (pages 94-95) of the Art of Electronics 3rd Ed., I'm having difficulty understanding how to calculate distortion of a grounded emitter amplifier. The book says: ...
3
votes
1answer
693 views

How to determine op-amp gain with active feedback?

The Howland current pump uses an op-amp in the configuration below with a resistive feedback network which gives me the gain show below: But if I decide to swap the feedback resistor for an ...
2
votes
1answer
74 views

Power Dissipation of Op-Amp

If we look at the output stage of the MP111 op-amp it's just 2 MOSFETs in series. I'm curious why the power dissipation of the device isn't simply \$R_{\text{ds(on)}} \times I_{\text{out}}\$, but ...
0
votes
0answers
45 views

Confirm re model of transformer coupled BJT amplifier

Could someone confirm my conversion of this transformer coupled BJT amplifier into a \$r_e\$ model? simulate this circuit – Schematic created using CircuitLab I get \$I_E\$ = 3.11mA and \$r_e\$...
0
votes
2answers
75 views

Best Guesstimate for Capacitor Replacement [closed]

I'm repairing an old (circa 1960) console hifi system for my parents. I'm no expert but also not totally incompetent. It originally came from Sears, I do not know the model number, nor the power ...
0
votes
1answer
69 views

How can I calculate V1 and V2 in this circuit?

How can I calculate V1 and V2 in this circuit? This is what I tried so far: Calculate the voltage of R5 through voltage divider but I didn't find the way, I was looking about second OA circuit but ...
0
votes
2answers
56 views

Amplifier Output Clipping

When an amplifier output clips at a certain voltage, does that mean the maximum voltage that its output can provide is the voltage value where the clipping occurs?
0
votes
1answer
35 views

NMOS/PMOS Characterization

I have some questions regarding NMOS/PMOS characterization. I'm designing a common source amplifier using gm/Id method and since it requires characterization, I did so but using minimum lengths and ...
0
votes
1answer
36 views

4.5µA Li-Ion Battery Protection Circuit

I tried to simulate the circuit given in your design note "https://www.analog.com/en/technical-articles/battery-protection-circuit.html" According to the designer, the cut off voltage is 3V but the ...
0
votes
1answer
59 views

Q: LM833N acting weird above 9V

I have a quick question as to why my LM833N is behaving as such. Any time I try to power the amplifer with 9V or over nothing happens, its just a flat line on its output like its turned off or ...
0
votes
1answer
47 views

Confusion with a simple two stage amplifier design example

I have been following a lecture on net about a two stage amplifier example. It is basically a BJT amplifier with a PNP emitter follower as shown below. I named some of the nodes for clarity: The ...
1
vote
1answer
121 views

Can't find source of hum in left channel of bluetooth speaker that I built

I have an RN-52 bluetooth audio module - https://cdn.sparkfun.com/datasheets/Wireless/Bluetooth/rn-52-ds-1.1r.pdf I am using it with this amplifier - https://images-na.ssl-images-amazon.com/images/I/...
0
votes
2answers
38 views

Calculate linear phase when given in decibel

The datasheet of the LT6230 shows the opamps phase lag in decibels (page 14). The datasheet does not give a formula to recalculate the angle in degrees, so can I just assume the following being the ...
1
vote
1answer
39 views

using TTL to drive LED

I have a TTL signal of 1 V, and I need to drive an LED by amplifying the TTL to 3 V. I used the following voltage amplifier circuit with Rc = 10 KOhm and Re = 1 kOhm. The DC input I use is 3 V. ...
0
votes
1answer
37 views

Hall sensor for slowly varying magnetic fields

I am trying to measure the change in the field of a permanent magnet (at about 50 mT) due to temperature fluctuations at room temperature (timescale ~ mins to hours). The sensor I am currently using ...
0
votes
1answer
54 views

Mos amplifier numerical

Can anyone please explain how do I get this variation of Ix vs Vx curve?How do I determine whether the current will be in positive region or negetive?
-1
votes
1answer
40 views

Mos amplifier output characteristics

I have a problem in the first region where M1 and M2 are in saturation.If both the NMOS are in saturation,how can the Vout be VDD.Shouldn't Vout be close to 0V as the pulldown current is much greater ...
0
votes
2answers
45 views

Mos amplifier region of operation

In the solution presented I have doubt regarding the 3rd region where both Mos are in saturation.When M2 shifts from triode to saturation how can we say that that the Vout will still be increasing?Isn'...
0
votes
1answer
20 views

Adafruit audio FX mini and 2.5W amplifier

I am connecting Adafruit's Audio FX Mini board to a small Adafruit's amplifier. In order to save some power when the sound board is not outputting any sound, I wanted to connect ACT pin of the sound ...
0
votes
2answers
46 views

SPICE circuit to find AOL and noise gain of Transimpedance amplifier

In Chapter 10 of Art Kay's book "Operational Amplifier Noise", he gives a SPICE circuit (pp.179) that can be used to generate the noise gain, AOL, and current-to-voltage gain. Could anyone explain to ...
0
votes
1answer
75 views

What are these inputs for this audio power amplifier?

I have made a preamplifier with filter but before asking that question I decided to open a specific question about a MOSFET audio power amplifier. It seems an old one and I cannot find its data-sheet ...
0
votes
0answers
52 views

Using a single channel on a 2 channel DAC + Amplifier

I am planning to use an external DAC + amplifier combo to output mono sound from my microcontoller. The ouput from the amplifier would be connected to a single speaker ...
0
votes
3answers
81 views

What could be a near rail-to-rail opamp with very low voltage for this use?

What could be a near rail-to-rail opamp with very low voltage for this use? LM386 seems to be out of limits for my needs. How do I choose it from datasheets? What values are important (of course ...
6
votes
2answers
165 views

How to design a circuit starting from a block diagram?

I am struggling with the following self-study problem, taken from The Analysis and Design of Linear Circuits (8th edition). There are two things that shock me from this problem. We need to get a ...
2
votes
1answer
124 views

Reasons for choosing a transistor instead of an op-amp as a buffer

I have often seen circuits for guitar pedals that use an emitter-follower configuration as the input and output buffer (see example below). If an op-amp can provide a greater input impedance / lower ...
2
votes
3answers
110 views

Differential to single ended audio signal

I'm working on an interface that will be connected instead of a speaker, input of my interface is differential, and output is single ended. I'm using the following schematics : R3 is the load to ...
0
votes
2answers
55 views

Why does these capacitances have no effect on the output of this amplifier?

Below shows a piezoelectric sensor connected to a charge amplifier: The text claims that the output voltage Uout is to a good approximation only charge q which is going to be measured divided by the ...
-1
votes
2answers
55 views

How do i drop voltage in series?

I have a 12v PSU output voltage that uses around 9A, i need to decrease this voltage to 11v but keep the amperage the same, any ideas? thanks
0
votes
1answer
30 views

What happens when the DC supply of this common gate amplifier is switched off?

The Vin in this case is a 200mV peak to peak sine wave signal. what happens to the gain of the amplifier when the DC supply of 10V is switched off?
0
votes
1answer
42 views

PWM Comparator types for Class D

I've started simulating a Class D amp, but it seems the MAX999 (I saw recommended elsewhere on this site) isn't working. Could anyone point me in the direction of why? I swapped in an LM311 which ...
0
votes
1answer
100 views

Designing two stage CE amplifier with negative feedback [closed]

I'm trying to design two stage ce amplifier with negative feedback using 2n2222 transistors. The circuit must have certain voltage gain, Rin, Rout, Vcc, low and high frequency filter. This is the ...