Questions tagged [analog]
Analog circuits have a range of voltages, rather than just two as in digital logic.
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Input impedance of High - Frequency Amplifiers
I have a question about the choice of the input impedance of a high frequency amplifier.
In general I know from elementary analog electronics courses that it is good for an amplifier (for instance an ...
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XADC Current Sensing Reference Design
Please refer to this reference design for AC701 (snippet below).
The schematics, specifically the current sensing sections in pages 34-36, show this:
I want to understand why, for the REF output of ...
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Is there any way to match Vth of 2 mosfets with different aspect ratio?
For the floating mirror circuit to work properly, the threshold voltage of M1 and M2 must be the same. However, (W/L)1 ≠ (W/L)2. So I thought to get a first order matching I can match L1 and L2 (to ...
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Can Vds ever becomes negative in mosfet?
Due to the symmetry in mosfet, source and drain are interchangeable. So we define the source of nmos is the terminal with the lower voltage. So if we force Vds to become negative the drain and source ...
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Logarithmic Multi - Stage Amplifier
let's consider this logarithmic multi - stage amplifier:
Each stage is an amplifier with this mechanism: if the input signal is small (under a certain threshold), it is amplified with high gain A; if ...
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Check the position on analog servo [closed]
In analog servo, how to set the position with hands then check the position in raspberry pi,yes i know potentiometer can do that but i want with servo motor.
Now, i can increase decrease the speed of ...
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Current sensing using XADC
AC701 Schematics
Refer page 40 of the schematics. Here for Vccint- the regulator is switching at 250 kHz.
page 34 has the sensing signal conditioning for that the inst. amp used is INA333 which ...
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Is ok to use a CMOS Analog multiplexer with voltage from a sensor as an input?
So, I got an analog circuit with an IR sensor that generates a voltage in output. The voltage is a measure that must be read with a microcontroller (I use Arduino Zero). This is the sensor.
As you ...
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Single Supply Class-A-Amplifier circuit to amplify voltage signal alternating around ground
I have a sensor which outputs a voltage signal alternating a few millivolts around zero volts and want to design a circuit which prepares this signal for processing by a microcontroller like in the ...
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Thermistor probes wired in parallel
I have three temperature probes.
Each probe consists of four sensors (NTC) with a common wire.
The sensors wires are connected together and the common wire for each probe is available:
The wiring ...
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Op-Amp settling time in bits
I was reading through this and was a bit confused. What do they mean by
"took forever to settle to 10-bits (0.1%)"?
How is 10-bits = 0.1%
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Regulating power on load
I have a blackbody emitter, for which I have to regulate the temperature (to get a constant spectrum out of it) - the only way to do this in our system is to regulate its power (we can't measure its ...
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Generating negative voltage rail using P7805 DC-DC converter
I need to create a negative voltage rail (from positive supply rail), say -5V to keep a P-MOS transistor in ON-state even when the voltage on its [S] source is 0V. So I found this schematic in an ...
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Parasitics extraction
What does "parasitics extraction" mean in terms of Virtuoso simulation with Calibre?
I know that this simulation is used to have an accurate model of the circuit.
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Analog exponential convert for MFOS VCO
I'm trying to understand the exponential converter in the MFOS VCO. Here is a link to the complete MFOS Noise Box synth schematic.
http://musicfromouterspace.com/analogsynth_new/NOISETOASTER/...
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Power efficient oscillator topologies?
I'm building an oscillator for a battery powered capacitive position sensor and I need it to have a high swing (>800 mV) at the output while keeping power consumption low enough. I'm feeding the ...
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Reading voltage (0-5V) using the Arduino Uno analog input and overvoltage protection for this pin
I need to measure the voltage on the 0-5V power line using the Arduino UNO analog input.
As I understand it, this can be done simply by connecting the "+" power line to an analog pin, without using ...
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Weird resistor with dots around it on the schematic
I was looking through the LTC4041 datasheet and saw this:
The 10mOhm resistor with the two nodes really close to it - is that a "special" resistor or something? Why have they drawn it like that?
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Providing input to clipper circuits
I was reading about diode circuits for clippers
According to my observation, I felt only sinusoidal signals are used to give the input.
So, my question is can any wave,for example, square wave, ...
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0-10V on RJ45 jack - bad practice?
I'm developing a control unit for ventilation systems. Beside switching those fans with a relay they are often controlled with a 0-10V analog signal. Now I found a product that uses a RJ45-plug to ...
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Multi-stage fully differential bandpass filters
I've recently been doing a bunch of research on analog filtering in preparation for a data acquisition system I'm building. For context, while I'm fairly comfortable with FPGAs and digital/computer ...
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RC circuit intuition
How to intuitively guess the output waveform of a rc differentiator to a ramp input? I know it will be a constant value if RC is very small but that's from calculation. How can I intuitively guess it? ...
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How do I change the output voltage of the LM7805?
I read in the LM7805 datasheet that I can change the output voltage to not only 5 V, but to another value by changing the circuit resistance. How do I do that?
From what I understand, to change the ...
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Any way to build Analogue Multiplexers using MOSFETs or JFETs or BJTs
Here's my requirement:
I need an analogue switch that can do SPST/DPST/DPDT with very low On-Resistance (<10mOhms). There would be current flowing through this switch, albeit in the range of a <...
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Are there well known simple operationnal amplifier circuits designs to make purely analog squaring amplifier (for experimental analog computing)?
In order to make analog calculation (for analog regulator simulation), what would be the means to make an squaring amplifier ?
There is an obvious solution with a multiplier circuit as pointed
here;
...
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Current Sensing Amplifier Circuit explained
I've been trying to understand why each every comment is in the circuit shown. I understand that the amp is taking the voltage drop across the Rsense and amplifying it such that the current across it ...
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DC/DC: Analog --> PWM 12V [closed]
I'm looking for an IC that can convert an analog signal to a PWM signal, i.e.:
Ui = 0V --> DC = 0%
Ui = 6V --> DC = 50%
Ui = 12V--> DC = 100%
Anyone who knows an IC for this?
Thank you
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Multiplex Analog pin and digital pin on single pin
I have to manage one single analog pin with other digital IO.
I am using a PIC micro, where I have utilized all the pins and I want one more pin for analog input. At the current stage, I can not ...
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To find theRMS noise voltage in a circuit, can the measured RMS voltage be subtracted from the RMS voltage of shorted probes?
I'm trying to estimate the SNR of a circuit, which includes measuring the noise power of an analog trace. Right now, I'm attempting to measure the noise with a high bandwidth scope probe, ac coupled, ...
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Why are active loads used for transistor amplifiers?
I get it that voltage drop across active loads are less compared to passive loads and at the same time they offer high small signal impedance thereby increasing gain.
I cannot understand why DC ...
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Op-amp circuit to control gain of two analog channels with one single-section potentiometer
I'm working on designing my own headphone amplifier with extremely high fidelity. One thing I want to incorporate is a circuit to control the gains of the two channel's using one single-channel ...
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Which is the preferred approach to PCB layout for signal vs power traces in analog circuits, and things to consider?
I have had to layout 2 layer PCBs several times now for analog signals, and am just beginning to learn the process. I often face a similar question in one form or another with regard to laying out ...
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Why isn't there any 9.5 digit multimeter or higher?
Why can't you buy a 91⁄2-digit multimeter?
Isn't there any need for it? Is a 81⁄2-digit multimeter the latest high end you can buy? I have tried Keysight, Keithley, and Fluke, but there is nothing ...
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Low voltage drop current limiter for charging supercaps with a MOSFET
I have an RPi that I want to give enough juice to auto shutdown when the power goes down. For this I'll use 2 supercaps of 6F (2.7V) in series, giving me plenty of time. Now, I was wondering if I ...
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When to use P-Type current source(using pMOS) and when to use N-type current Source(nMOS)?
I am referring to Prof. Behzad Razavi Lecture https://www.youtube.com/watch?v=GAvZLyii3aw&list=PLiDoPUX9nLkIw9EnIv_3K19wlcyJ6msYd&index=2 (Minutes 19-26)
Prof. says to use nMOS when we draw ...
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Will a parallel capacitor short a resistor?
In the configuration above, SOL_IN is the rectified output of a solar panel (so dc).
What's more important is R1, which is a low resistance sense resistor used to measure the current from the solar ...
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Guitar to MIDI conversion
I am wanting to measure the pitch of a single guitar string and convert into MIDI within 10ms.
FFT takes too much time, I was wondering what other options are worth looking at? The main issue is ...
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Opamp output on loaded and unloaded cases
I have a design project to rotate a motor. In order to do that, I have designed a very simple but smart circuit. However, in signal comparison stage, if it is unloaded, i.e. not connected with the ...
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Imposing AC ripple on DC voltage
I am trying to impose an AC ripple of 0.9V peak to peak (1kHz) on 36 volts DC supply for one of the test using following circuit.
Without any load connected, I get the proper AC imposed DC voltage ...
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Best way to connect balanced audio line to ADC (with volume pot)?
Sorry for this more longish question: I'm currently collecting some ideas for my next project where I want to connect an external balanced audio line level signal to an ADC with differential inputs (...
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Can we use both FFT and PSD to obtain a random signal's frequency domain representation?
I always encounter random noise frequency domain representation as PSD(not FFT), something like in the below plot:
Without diving into math too much, practically speaking can we always use FFT ...
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Practical examples to determinism and periodicity of analog signals?
What I understand from deterministic signal is that we can define it as a function. Same thing is valid for a periodic signal. But periodicity and determinism are are treated as independent categories ...
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How to limit current while almost keeping voltage same
I am supposed to design a power supply to a project. I have 3 alternative power supply designs for this purpose. However, one of them sucks huge current while giving enough current. My design is given ...
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How to find the RMS value of a sine wave with DC offset and retain the negative sign
I'm trying to build a Quadrature setup where an input signal is mixed with a reference signal that is in-phase and another one out-of-phase by 90deg.
The idea is to extract the real and imaginary ...
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Momentary over-excitation voltage circuit
I want to control an electromagnetic brake (fail-safe brake) used along with a servo motor. A microcontroller will control the trigger signal for the electromagnet coil.
Electromagnet requirements:
...
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feedback loop component dc converter
Consider the schematics below, the switching frequency is 250KHz, So, The cross over frequency be 250/5 = 50KHz. My ADC is able to sample at 1MS/s which is good as from the SNR perspective.Now, the ...
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Colpitts oscillator: how to reduce amplitude thermal drift?
I have built this circuit, supply ±12V:
I am using a LM6172 amplifier.
I have found the transfer function of the filter involved:
\$H(j\omega)=\frac{1}{1 + \frac{R_3}{R_1} - L\omega^2(C_2+C_1\frac{...
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Lithium Ion Battery Charger and Power Path Management IC
I am to analog electronics. I am building a circuit that has a lithium ion battery. I understand the importance battery charger in battery management.
My question is how does a designer set ...
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SENT (Single edge nibble transmission) signal to analog signal conversion
I'm currently getting a SENT signal output feedback(IC MLX90367 used in the simple actuator) from an actuator. For closed loop control, I have to feed this signal back to the motor controller. ...
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Dual slope edge detection for a phototransistor
I want to detect sudden changes in light level using a phototransistor. The goal is to transmit information optically using the timing of the transitions, ideally using an LCD screen.
LCD transitions ...
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