Simply the ratio of output signal to input signal, this dimensionless quantity is a measure of the amplification of a signal which may be represented by voltage, current of may even have a digital representation. A very general concept sometimes used to describe attenuation (when gain

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37 views

variable gain amplifier for ACS712 current sensor

My project requires measuring current ranging from 30mA to 500mA. Im using ACS712 (5A)current sensor for this purpose. Since the sensitivity of the sensor is typ:185mV/A, measuring current as low as ...
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2answers
69 views

Why Doesn't This Op Amp Preamp Circuit Amplify?

I have the following circuit as part of a class D amplifier: simulate this circuit – Schematic created using CircuitLab I couldn't get the amplitude of Vsig to display, it is ~.447Vp, to ...
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1answer
48 views

Differential gain of amplifier with current mirror

Consider this pdf document, pages 58-59-60. It is a differential amplifier with a current mirror as active load. According to that document, if I take the unbalanced output in the right-hand branch ...
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55 views

Amplifying Signals to a Certain Voltage

Say I have some high frequency low signals and I want to amplify them to peak at +/-9V or something. Yet the chosen Fully Differential Opamp is only powered at 5V. So even if the Opamp were to go to ...
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1answer
41 views

Equivalent impedance calculations from “both sides”

A circuit I have been working with lately consists of a binary counter being fed into an Op-Amp DAC, shown below. One of the major issues with this design is that the input impedance of the DAC will ...
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60 views

Trying to get a gain of -2

What capacitor will this circuit have a gain of -2 at 40 kHz? The op- amp has an open loop gain of at least 10000 at this frequency.
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0answers
57 views

Do we ever need to use multimeter's transistor current gain measurement feature?

Many cheap multimeter have this feature that they can measure the hfe of a NPN or PNP transistor. Does anyone ever need to use it? I mean, when we design something using discrete transistors, we look ...
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1answer
41 views

Determining DC gain of single supply op-amp (no AC component)

I'm building a homebrew PIC programmer, and want to support devices with varying Vpp voltages, so I'm using the DAC output of a PIC16F1825. But the PIC is supplied with a +5V Vdd, so that's the ...
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2answers
88 views

Why hFE(DC gain) shown on multimeter isn't equal to the datasheed hFE?

I have a tip122 and discovered my multimeter uses Vce=2,8V DC and Ib=10uA for its hFE test. When I insert the transistor on the terminals for hFE test, the gain on the multimeter alternates between 1 ...
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1answer
30 views

How to calculate the gain for a load cell to be used with instrumentation amp?

I was hoping someone can give me a step by step process for calculating the gain of my load cell.Here is the datasheet to it LoadCell datasheet. I also plan on using the INA125p instrumentation ...
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3answers
108 views

Audio amplifier limiting output power

What I have: A transformer rated at 150VA / 30V (center tapped) / 5A Speaker rated at 30W / 8 ohms (measured 6.3 ohms with my multimeter) Will use class AB amplifier: LM4780 ...
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0answers
15 views

Multiple active filtering or single active filtering

I am using an op amp(Inverting configuration) to get a gain(V) ranging from 20 to 160 using a multiplexer to choose a different R2 value. R1 is a 1K pot which is set to .5K and the MUX has 8*10K ...
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4answers
277 views

What is the typical error of a voltage follower opamp

I am trying to identify design elements that might have error from unit to unit. In the design I am looking at, there is a voltage follower configuration for an opamp (in this case, an LM2014), which ...
2
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1answer
67 views

Calculating the gain and phase shift of a phase shifting circuit

I want to calculate the gain and the phase shift of the phase shifting circuit below. My approach is to derive equations to different meshes using Kirchoff's law, and then calculate the ratio between ...
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0answers
45 views

op-amp gain is less than 1

i am trying to make an op amp circuit with 0.1 gain. i have make the circuit using UA741. the problem is that no matter what i do the gain for the circuit does not go below 1. If you need any extra ...
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2answers
84 views

Microphone preamplifier doesn't give expected gain

I was designing a microphone pre-amplifier circuit for Wireless Noise Monitoring application. I used an electret microphone AOM-5244L-R-53724 (datasheet: ...
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1answer
36 views

Detect incidence angle with an antenna array

Having an antenna array, how can we determine incidence angle of an incoming signal. I know it is related to the phase of the signal in each antenna but I only found information about how to send a ...
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0answers
60 views

Calculating the actual ECG Voltage from ADC values in the SHIELD-EKG-EMG by Olimex

I'm using this shield with my arduino to acquire ECG signals https://www.olimex.com/Products/Duino/Shields/SHIELD-EKG-EMG/. I am able to get the waveform in a processing software. Now my problem is ...
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0answers
51 views

Preamplifier active volume and balance control

Hello everyone here is a pre-amplifier with active gain and balance controls, now its a derivation of the above circuit but with added resistors for balance control too. Would do formula for the new ...
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2answers
74 views

How to control op amp gain with atmega 32 MCU?

I am attempting to control the gain of an amplifier circuit I am building programmatically. I am using the atmega 32 MCU to control an LCD screen and take input from some buttons. Basically, I would ...
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3answers
160 views

Can someone explain this gain & offset op-amp circuit?

I'm having trouble understanding the circuit in the photo below. I know that it's a gain and offset amp designed to convert 0-2.5 V range to +/-10 V range (hence it has a gain of 8 and an offset of ...
4
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3answers
549 views

Expressing Gain in Decibels?

1) Why does power gain use a coefficient of 10 unlike the other two? 2) Why can't power gain be negative?
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1answer
131 views

Non-inverting amp Gain

I am making a differential amp with a non-inverting amp with a gain of 4.9 with the use of an AD822 which is a dual rail-to-rail op amp. My input signal on the diff amp is on the range of 2.5V to ...
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1answer
163 views

How to Calculate maximum distance between transmitter and receiver in wireless communication

how to calculate maximum distance between transmitter and receiver in free space radio communication by having transmitted power, antenna gain and noise-to-signal ratio ?
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0answers
35 views

Load cell Sensitivity

Is there a way that I could exactly know what is the value of the sensitivity of a load cell(mV/V)? The only characteristic I know is its full capacity which is 200kg and written on the sticker. I ...
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2answers
283 views

Op Amp's Negative Power Supply to Ground

I am using a standard 741 Op Amp from TI. For me to amplify any signal, I am required to set +Vs = 15 Volts and -Vs = -15 Volts. I am now concerned as to what will happen if I connect -Vs to 0 ...
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1answer
87 views

IR Led & Phototransistor pair bandwidth issue

I'm trying to sense IR wave with a phototransistor circuit. The circuit operates well under DC operations (I mean 3.3V through inputs). However, if a square wave is supplied from UART input, after ...
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3answers
112 views
3
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3answers
362 views

Amplifier design with three stages

As a project for my electronics 101 class, I've been assigned to design a three stage amplifier using bjt transistor to achieve a gain of 150 and input resistance of 100k and output resistance of 50 ...
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0answers
21 views

A closed form for calculating shaping gain

As we know, in a communication system, we can divide the overall gain into coding gain and shaping gain, but I have not seen any closed form formula for calculating shaping gain, but the definition ...
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2answers
91 views

Amplifier gain too HIGH?

I have this circuit : Two common base amplifiers for amplifying frequency in FM range (88 to 108 Mhz). The Problem is, as seen in the figure, I am getting an output of 1.5 V for an input of 10 uV. ...
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2answers
79 views

Is possible to use wave guide to decrease beam width?

If I use a normal 1/4 monopole antenna "30 MHz for example" and cover it with metallic wave guide has a narrow beam width, should the gain increasing according to this formula below? $$G = 10 \; log ...
0
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0answers
45 views

Is possible to get very narrow beamwidth antenna?

Is possible to make 60 dBi sector or patch antenna by make its beam width 0.17°/0.17° only ? how to calculate ideal dimensions against frequency at this range of beam width ?
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3answers
107 views

Calculating gain of multiple antenna system

Some radars have thousands of antennas, there are also some routers that have multiple antenna systems. But I want to know how to calculate total gain of multiple antennas in a system? Is it simply ...
0
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1answer
147 views

Just I want to understand gain, power, link budget

I am a beginner, I am confused about calculating the nessecary gain and power and sensitvity to overcome path loss at certain distances. the first thing what does gain mean ? I am not talkink ...
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1answer
88 views

If I connected N numbers of amplifiers each have X gain 'dB“ and Y power ”dBm", how to calculate total gain and power?

sorry for bad description, I am a beginner. my question is just for knowledge and I did not test anything. If I connect for example 3 amplifier , each one has 60 dB gain and 15 dBm power. can we ...
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2answers
88 views

Prevent loss of Large Signal Voltage Gain at low Rload

Operational Amplifiers (opamps) have the tendency to drop their Large Signal Voltage Gain when the load is too low. This behaviour is usually described in the datasheet. Loads of 500 ohm and lower ...
2
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3answers
399 views

Why is an op amp's bandwidth higher at lower gains?

If I build a resistor network where the op amp has a lower gain, it is able to maintain its gain for a larger bandwidth. Why?
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1answer
175 views

Op-amp and manipulating its linear output range

First of all let me give some background on the problem. I'm not a native English speaker and I have a basic understanding of amplifiers and op-amps. I am having trouble with one problem in English ...
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3answers
387 views

Effect of non-inverting op amp on the AC and DC components of the input

I was wondering what the effect of an op amp like the one in the image below is for an input signal such as \$0.5\sin(2000\pi t) + 0.5\$ V? Are the DC and AC components amplified with the same gain? ...
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1answer
133 views

Gain bandwidth product of op-amps

What is the gain bandwidth product of an amplifier? (What does it mean?) How can I find the gain bandwidth product for an amplifier which has a gain of -100?
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2answers
79 views

How to achieve large gain in the transfer function with OP-AMPs?

My transfer function is: $$ \frac{-115.298}{1+5\centerdot10^{-4}s}$$ To achieve the denominator I used an inverting op-amp with Rf = 1k, Cf = 0.5uF (ceramic, and both in parallel) in feedback and R ...
1
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1answer
85 views

What is the current gain of this op-amp circuit?

I just happened to see this circuit in some lecture slides and I thought I could solve it. Unfortunately, I've been trying to check my result with an ideal simulation in LTspice and all my attempts ...
8
votes
2answers
404 views

Common Emitter not amplifying

I am trying to make a 27 MHz carrier wave transmitter from a crystal oscillator and a secondary amplifier. Thi is the complete circuit: simulate this circuit – Schematic created using ...
3
votes
1answer
92 views

What exactly is (Horn) Antenna Gain

I was doing an experiment for finding the radiation pattern of Pyramidal Horn Antennas at RF frequencies(as part of my course curriculum). There I came across the Friis Transmission Equation What ...
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2answers
201 views

Op amps with 1000 gain and 10 volt out

I've been looking for a part that I can boost a 10 mV signal to a 10 volt signal using a single op amp, so far most of the op amps I've found only meet the gain requirements, but cannot output 10 ...
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3answers
203 views

Amplifier design: feedback with unclear poles

When designing a closed loop amplifier for audio the poles of the open-loop transfer function are usually only vaguely known. \$\frac{1}{(s-p_1)(s-p_2)...}\$ These poles can be modeled as \$RC\$ ...
1
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1answer
125 views

Modeling diode connected transistor in differential amplifier

I have question about the analysis of common-mode gain of BTJ differential amplifier with active load on the Sedra Smith book. In this book, the differential-mode gain \$Ad\$ is derived based on the ...
2
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1answer
95 views

Op Amp magnitude of gain proof

I've been working through a proof but I'm stuck on one of the last steps. Consider an inverting op amp with a feedback resistor \$R_f\$ in series with a capacitor and resistor \$R_1\$ simulate ...
2
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1answer
79 views

When the Gain Margin is negative, for what range of frequencies is will the output resonate out of control?

If your system/transfer function has greater than zero gain for the frequency associated with -180 degrees phase, the system is said to be unstable. What does this mean for other input frequencies? ...