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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)

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37 views

Determining control voltage of variable gain amplifier to achieve fixed output amplitude

I am wondering if there are any well known methods for determining the control voltage of a variable gain amplifier required to achieve a constant amplitude output without requiring prior knowledge of ...
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1answer
127 views

Sound distorted from amp configuration, and one transistor variety getting too hot

The sound is distorted from my configuration. The transistor I'm using is an MPF4393. I need to add resistors and capacitors and how do I get more power (to make it louder) What should I add? Also ...
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57 views

Voltage controlled amplitude problem - JFET circuit

I work on a function generator project. It generates waveforms such as sine, triangle, rectangle with PWM regulation, saw. I would like to digitally adjust the signal output amplitude. Input signals ...
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38 views

Amplitude control in a signal generator

A am working on an FPGA based function generator and I am aiming for max frequency to be higher than 10 MHz, hopefully 30 MHz. I have implemented most of the functionality except amplitude control. ...
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2answers
65 views

Using a fully differential amplifier as a differential ADC driver

Regarding my previous question, I decided to use a “fully differential amplifier” to obtain a voltage gain of 10. The source and ADC are also differential. The source is unipolar and its output ...
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3answers
68 views

What can be alternatives to BF494 transistor?

I am currently working on a project which involves a RF Amplifier. I found BC494 to be quite suitable for the same. Though, I am looking for its alternatives since I couldn't get one of these.
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66 views

Are there any benefits to amplify the signal for this case?

A force transducer together with its amplifier designed for a full scale load such that it has -5V to +5V range as output. But it is only used with loads outputting -200mV to +200mV. A data ...
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1answer
29 views

Error Amplifier Gain

I was studying the "SG3525" IC and its functions, and I encountered this issue: In the "Error Amplifier" section of the Datasheet, there is a parameter that named "DC trans-conductance" which it is "...
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53 views

Amplification problem

I am using an instrumentation amplifier AD620ANalong with another amplifier TL084CN in series. Both have gains of 100 which essential for me since the input is in microvolt range. The frequency is 87 ...
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1answer
36 views

Discrepancy in my dB SPL calculations

Having read through this post I tried an experiment. I connected a Extech sound level calibrator to a Type 4189 microphone. The output sensitivity of the microphone is 50 mV/Pa,-26 dB ± 1.5 dB re ...
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2answers
73 views

Find output impedance of BJT amplifier

I need to find the output impedance of the BJT amplifier as shown below: The equivalent small-signal circuit looks like the following: I know that the output impedance is $$Z_o=R_{E1}\ ||\ (R_{E2}+...
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3answers
113 views

0-2v to 0-10v amplifier

tl;dr: I want to understand op-amps better! How do I choose the magnitude of resistors? 1k, 10k, 100k, etc.. I made a schematic to play with an In-amp to create a gain of 5. What other ...
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59 views

Why my HB100's amplifying circuit can't generate more than a signal of 200 Hz?

I want to amplify the HB100's IF signal with the circuit shown below, but when I test my circuit I can't read more than 200 Hz, maximum 300 Hz. The circuit works with the OPA2365 integrated circuit at ...
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32 views

Suitable antenna for XBee S3 PRO 900hp working at 900MHz frequency

We are currently working on a project using 3 XBee modules. One is like a data center or the master of the other two XBees. We did a range test with a master and a slave XBee on an open field using a ...
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3answers
75 views

How can I increase the AMPs in a transformer less power supply

I am very new to electronics and trying to do something which I am not much aware of yet. I have a NodeMCU (based on esp8266) for which I need power supply of 5V and it required I guess more then ...
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1answer
88 views

Generating a constant-amplitude triangle wave from a square wave

I have designed a circuit that can generate sawtooth and arbitrary duty cycle pulse waves controlled by some variable DC current source \$I_0\$, giving a frequency proportional to this current. The ...
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39 views

Appropriate driver amplifier to amplify an FPGA pin voltage for RF applications

I'm trying to built a nanoseconds RF transmitter using an FPGA and an up-converter. However I don't know the correct configuration (I prefer a single IC) in order to drive a nanosecond pulse (pulse ...
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55 views

Custom microphone amplifier poor high frequency response

I've designed and received a custom MEMS microphone amplifier PCB, but am having issues with poor high frequency response and very low sensitivity/gain. Basically the microphone stops picking up ...
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52 views

Amplification equation for AC coupled Common Emitter stages

Do anyone can tell me how to get amplification equation for this circuit of coupled common emitter amplifier? simulate this circuit – Schematic created using CircuitLab Edit 1 Equation for ...
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0answers
25 views

Voltage conversion between multiple orders [duplicate]

I have this circuit in which I want to convert the input voltage of micro order to volt. The circuit image has been posted. I have figured out the bandpass filter ( basically everything after the big ...
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1answer
130 views

I'm having trouble understanding the properties of this circuit

The objective of this question is find beta, which is ( Ic/Ib) The 3V is supposed to be 2.3V The 27 k ohm is supposed to be 20k The 230 ohm is supposed to be 230 ohm I first found Ib = 4.3 v- 2.3v /...
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0answers
88 views

Why resistor is used at the output of OPAMP?

I'm reading this note and in Figure 1(page 1), there are two resistors R5 and R10 whose use I don't understand. From my understanding, R5 would cause offset due the input bias current and R10 would ...
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3answers
114 views

Conversion from microvolt to volt [closed]

I have a circuit which has an input of voltage of the order of micro. I want to convert it into volt order. I am using an instrumentation amplifier AD620 with gain of 1000 to first convert it into ...
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1answer
93 views

Problem in temperature transmitter because of VFD (Variable Frequency Drive)

I made an amplifier of PT100 bridge which operates on 24V DC supply and gives 0 - 10V DC for 0 - 400°C when tuned. The circuit is as follows : Here P2 + and P4 S+ are shorted and P4 S- is left open....
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53 views

Simple push-pull problem

I've made a circuit based on the schematics below, which works fine at simulation. The goal is to add some extra oomph on the output of a LT1210 opa (V1) to drive a piezo element at higher voltages ...
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1answer
34 views

Voltage controlled current source question

Need to find ratio Vs/Vo in terms of the 3 resistors and gm. I have expressed Vo/Vs as gmvgsR2/Vs but am unsure how to express Vgs in terms of the R1, R2 R3 and gm.
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57 views

alternative amplifier for vibration exciter (shaker)

I am using a second-hand LDS V201 permanent magnet shaker, and would like to use this to test and validate some monitoring equipment. I would like to generate signals suchs as sweep sines, but these ...
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37 views

Negative feedback optical amplifier

Why the feedback network is necessary in this optical amplifier ? How the circuit would work without the feedback photodiode ?
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1answer
23 views

Bluetooth receiver combining differential outputs to single ended (LR, N) to one (main) secondary amplifier

Hello I am new to this forum recently purchased a CSR8645 Bluetooth Module I have a Sony MHC GX Music system with AUX/MD Video Audio input (Left Right Ground). But in my CSR8645 ...
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2answers
55 views

using an electret microphone to trigger an LED

I would simply like to trigger (on or off) an LED based on the pressure level at an electret microphone, much like a stroboscope. The circuit should be as simple as possible (in terms of number of ...
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1answer
47 views

Op Amp Input Offset Voltage vs Common Mode Voltage

I would like to use an op amp AD8618 for a design, and need the input offset voltage to be low. For this op amp it seems fine with maximum of 65uV, but looking at the charts on page 6 etc, it seems to ...
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1answer
69 views

Possible to do this wiring for 2 speaker enclosures

(See update below the original question) (Original question) Hello, could anyone tell me if it's possible to wire BT receiver, 2 amplifiers, 4 Full range speakers and 2 subs like this? (Update ...
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1answer
31 views

If positively biasing amplifier does minimum voltage on input pins apply?

I am using an amplifier to bias a signal for an ADC. The signal range is -1.25 to 1.25 volts. I have the 2.5V precision reference for the ADC through a voltage divider to the inverting input of the ...
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2answers
795 views

Understanding class A amplifier waveforms

I am working on an audio amplifier but got stuck on to a basic of npn transistor circuit. Attaching a class-A amplifier circuit. Take a look here or here. I tried to simulate the circuit but as ...
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3answers
27 views

Variance in ECG lead resistance ; its effect ; CMRR

We are designing custom ECG electrode with flexible printed wires as to reduce wires clutter from different electrode. The manufacturer has made the patch but the resistance variation between all the ...
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2answers
59 views

Why the don't the theoretical and practical output of comparator match for small input?

I have been using TL084cn IC which is basically an amplifier IC. I was giving the input to it of amplitude around 450mv. This IC is capable of providing a slew rate of 13. The Vcc given to it ...
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1answer
33 views

How to convert from S-parameters to power gain?

With reference to the part below, which states 17dB gain at 500MHz for Vce = 12.5V https://www.digikey.co.uk/product-detail/en/stmicroelectronics/PD55003TR-E/PD55003TR-E-ND/1664253 It's data sheet ...
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1answer
50 views

Differential amplifier, superposition theorem, output derivation, what is a loop here?

So based on this article, when V1 is removed/grounded, in this picture. Is the loop number 1 drawn correctly? Or does R3 and R4 both belong to the same loop? I'm not sure how Vout2 was calculated. It'...
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1answer
66 views

How can you change grid voltage in a vaccuum valve?

I understand in a valve the level of amplification is determined by changes in the voltage of the grid or in the anode, but how can you change the voltage of the grid? And can this be done dynamically,...
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1answer
38 views

How does current sink help in biasing the differential amplifier?

Here M1 and M2 are differential pairs with analog input. When source resistor is used Rs M1 and M2 when Vgs is less than 0.7 Vt threshold M1 and M2 will be in cut off region and Vo1 and Vo2 will be in ...
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33 views

Creating an Input bias current return path (for an amplification circuit)

I have passive sensors (pyranometers that consist of thermopiles and measure sun irradiation, sensor specs are attached at the bottom of this question) that output a low voltage signal so I need to ...
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6answers
597 views

RC Lowpass Filter between Amplifier and ADC input

I have sensors (pyranometers that consist of thermopiles and measure sun irradiation) that ouput a low voltage signal so I need to amplify them using an instrumentation amplifier. I have chosen the ...
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2answers
136 views

Power Amplifier (Darlington) with Power and current limitation

I'm designing a power amplifier and the following circuit is the output stage. My output stage consists of two complementary transistors for both, positive and negative waves but for better ...
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2answers
50 views

connecting pam8403 and bluethooth module in series

I am new to this so I apologize in advance for any rookie mistakes. I decided to make a portable Bluetooth speaker. I have a pam8403 and a Bluetooth module: Both of them require 5 V input. Can I ...
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0answers
34 views

Buffered Voltage Divider VS Differential(Subtractor) Opamp

I'm trying to understand which one of these circuits is the best choice for measuring 400VDC signal using a microcontroller . But at first look circuit number 1 makes more sense since it is giving the ...
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3answers
72 views

Increasing amplifier power to increase sound level

I am reading a book by Everest and I dont understand one of the paragraphs: Increasing amplifier to achieve higher acoustic level can be frustrating. Doubling amplifier power from 1 W to 2 W is a ...
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0answers
28 views

Gain bandwidth product of amplifier in a DC scenario

I think I have a simple (but still to me confusing) question regarding the gain bandwidth product (GBP) of an instrumentation amplifier: Datasheet (AD8237) I have sensors that change their output ...
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2answers
62 views

Does this audio amplifier do differential filtering?

I was looking at this schematic for a two-channel audio power amplifier. The amp supports a bridged mode by means of an XLR connector and a switch. When the switch is in the XLR position, pin 2 (...
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1answer
29 views

Output changes wildly with input voltage in photodiode circuit

I am currently analyzing a photodiode sensor input circuit (not designed by me, but schematics drawn from a commercial product). I am currently simulating the circuit on TINA TI. While experimenting ...
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1answer
353 views

Why are the input and the battery connected in a transistor amp?

I'm trying to make a simple boost pedal for my guitar using the simplest schematic I found. I'm wondering why the input is connected to the +9v battery in this schematic through a 430kohm resistance. ...