Questions tagged [analog]

Analog circuits have a range of voltages, rather than just two as in digital logic.

291 questions with no upvoted or accepted answers
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121 views

Input & output resistance in voltage amplifier design

I'm currenly taking a course in Analog Circuits in the university and we got a task that requires us to design an amplifier, with characteristics that depend on our ID numbers. My amp should be a ...
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0answers
181 views

Help with deciding my layout for EMC tests and SI. Different alternatives

I am thinking of what way would be the best to layout my system in order for it to have the best SI and pass EMC tests. My system consists of two PCBs joint by a flat flex cable (up to 7cm) and these ...
4
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0answers
141 views

imx6q sabre board microphone

I have been trying to record audio using the circuit below. It is different from the normal microphone circuit in that the MIC_IN and MICBIAS are separate paths. I tried to connect an electret ...
3
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0answers
110 views

How to design analogue compensation for SMPS from Bode Plots?

In a complicated switched mode power supply where the transfer function is unknown, is there a way to design an analogue controller and compensation from the bode plot alone? I am having difficulty ...
3
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2answers
82 views

Getting a specific voltage output depending on the difference of two voltages

Can someone please help me come up with a circuit with the following specification? I need to find out the difference of two voltages (can be done using an op-amp). Then, if the difference is negative,...
3
votes
2answers
59 views

MOSFET pinchoff reduce current

I understand that in an n channel MOSFET as Vgs increases, electrons are attracted towards the gate forming an n channel. These electrons are responsible for the conduction of the MOSFET. As Vds ...
3
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1answer
57 views

Phase shift near saturation mitigation in input stage amplifier — How does this work, why does this work?

I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer. Apologies for the quality... this is the best scan I could find. The design is furnished with the ...
3
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2answers
539 views

Designing 4th order Butterworth Multiple feedback bandpass filter

I'm trying to design a 4th order Butterworth bandpass filter using Multiple feedback topology. The design requirements I am trying to achieve for this filter are; Q factor = 10, Av = 11, fc = 100kHz ,...
3
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1answer
163 views

Switching relay on and off affects analog sensor output voltage

I am working on an AVR project that involves measuring tempereture with an analog sensor (TMP36) and switching a heater on and off through relay to keep the temperature at desired level. However, I'...
2
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0answers
59 views

Op-Amps in custom current limiter acting strangely

I'm building a small current limiter (~20 mA). It's important that there is little drop over the current limiter and that the load receives almost the full supply voltage when it's pulling less than ...
2
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0answers
27 views

How do determine MOSFET parameters in LTSPICE

I am designing a phase locked loop on LTspice (which I'm new to), but have come across a snag in the procedure: Is there a way to determine the output resistance of a mosfet (as the I'm not able to ...
2
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1answer
63 views

Cascade of 555 timer with Control Voltage not triggering

Hi I'm currently working on a cascade 555 circuit, both operating in the monostable mode. I also want to be able to control the pulse width with a voltage so am using applying 0-5v to the ctrl pin (...
2
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1answer
79 views

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 ...
2
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0answers
172 views

PWM to synth control voltage improvements

Just built this little circuit to control my Moog Werkstatt. The plan is to make a MIDI-to-CV converter and add more CV outputs and of course a GATE output later. But before going further, I thought I'...
2
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0answers
82 views

High SNR FM demodulation

So I need to demodulate the FM signal from a sensor with highest SNR possible, at least 70-75 dB. IF is 10.7 MHz, max. deviation is 200 kHz but I can change those values if needed. Baseband signal ...
2
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0answers
93 views

How does the biasing work in a JFET based triangle to sinewave converter?

To those who haven't see this cool little circuit it employs the non-linearity and symmetry of the JEFET to clip a triangular signal to make it more sinusoidal Can someone please explain to me how ...
2
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0answers
69 views

Noise immunity of single ended analog voltage signal

I want to use a sensor with analog output in my design. The output of the sensor is a low frequency traingular wave (less than 300 Hz) and voltage vetween 0 - 5V. I need to carry the sensor signal to ...
2
votes
1answer
115 views

Simple analog circuit to simulate acceleration and braking behaviour in scale models

Background Scale-model road systems such as Faller https://www.faller.de utilise vehicles that follow a ferromagnetic wire embedded in the road surface. The vehicles operate at full speed and continue ...
2
votes
1answer
407 views

Dolby HX PRO implementation on existing tape recording deck

I'm experimenting the implementation of Dolby HX PRO's IC into an old stereo Fostex tape deck to improve high frequency and headroom capabilities. HX PRO works as a dynamic processor with the BIAS ...
2
votes
1answer
327 views

Programmable Electronic Load Design

I am trying to design a programmable electronic load for testing the PWM outputs of PLC controllers. The outputs operate between 5-36 V and 10-2000 Hz frequency. The output is supposed to tested for ...
2
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0answers
114 views

Trying to figure out what kind of input signal this loudspeaker amp circuit needs

I'm still trying to figure out how this door intercom module works. It's a 18y old siedle TLM 611-0 module, I figured out the mic part, there the audio signal is modulated onto the current the mic amp ...
2
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0answers
171 views

Asking about old russian amplifier internal circuit

I worked with an old russian machine in my lab, which contains an input from a photodiode with amplification circuit. The amplification is composed into 2 stages , the first with a JFET transistor ...
2
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0answers
284 views

Op-amp circuit saturates to negative rail and only passes positive side of input

I've been working on a spring reverb driver circuit, based mostly on figure 5 from this site: https://sound-au.com/articles/reverb.htm. While there's lots of information on the how of the circuit, ...
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0answers
3k views

MOSFET Parameters LTSpice

This is the LTSpice model of the Fairchild 2N7002 NMOS transistor. ...
2
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1answer
163 views

Noise in FET reverse-polarity protection for ADC

I have quite precise ADC circuit. I want to protect input supply voltage (not ADC input) from reverse-polarity using FET transistor as shown on the picture below. I wonder: is there any noise / worse ...
2
votes
1answer
419 views

ac voltage regulator

I'm trying to built a circuit that amplifies music from a phone to a headset, based om ambient noise level. So if you're surrounded by noise, your music volume will turn up and in silent surroundings ...
2
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0answers
1k views

How to find the resonant frequency of a human body?

I've read that the human body has resonant frequencies somewhere around 50MHz. I also think it would be interesting to look for values in other ranges like 10-100 kHz. I'm wondering how to build a ...
2
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0answers
554 views

Convert [-24V,24V] range analog signal to [0V,3.3V] range for ADC

I need to realize a circuit that converts an analog signal from [-24V,24V] to [0V,3.3V] before sending that signal to an ADC "MCP3208". I found the circuit in the picture below and it works perfectly ...
2
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0answers
100 views

Coupling vs Decoupling filter / Filter in-the-signal-path vs filter on-the-signal-path

I'm looking at designing an active analog filter module to be used/reused in my designs. Correct me if I'm wrong, but you can design a filter that is in the signal path that has the same frequency ...
2
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1answer
565 views

Shut down circuit sections

I am currently devising ways to shut off different circuit sections in an embedded circuit. Here is a breakdown of what I am doing and my initial idea. Currently I have a micro controller which is ...
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0answers
19 views

How can I add an offset voltage at the input of an instrumentation amp?

I want to measure the voltage of an H-Bridge Sensor. However, due to the manufacturing process, the bridge has an offset several times larger than the useful signal (it can easily measured by ...
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0answers
37 views

CMOS vs BiCMOS technology nodes comparison

I am trying to make a comparison between several technology nodes. More specifically I want to compare 28nm, 40nm, 65nm CMOS and BiCMOS processes. However I cannot find papers that compare some of ...
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0answers
35 views

Audio Loopback Dongle Sanity Check

The same circuit as in Explain “Audio Loopback Dongle"; I wanted to know how it worked. Anything I couldn't figure out I found out via CircuitLab's time analysis: simulate this circuit – ...
1
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1answer
40 views

Noninverting and the inverting Comparator

I was studying the Noninverting and the inverting Comparator with Hysteresis from the book "Practical electronics for inventors". NonInverting Inverting I understand that when the comparator has ...
1
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1answer
39 views

Design of Fully Differential OTA Circuits

This is the equivalent model of an ideal single-ended OTA: Now, this is the equivalent model of an ideal fully differential OTA: Now, is there a rule for getting a certain circuit with a fully ...
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5answers
115 views

Basic ternary circuit to light three LED’s?

I need to design a circuit that can light three different LED lights to simulate a traffic signal using two inputs. The first input is either -12v, 0v, + 12v. The second input is always on and it’s ...
1
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0answers
54 views

Suitable resistance values for an analog IC

I was reading a chapter of the book "Continuous-Time Active Filter Design" about analog filters design. Let's consider the following band - pass filter, in which its inductances may be simulated with ...
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0answers
26 views

Purpose of LLD on GM ratemeter

I'm confused as to the purpose of the LLD (lower level discriminator) setting on a ratemeter GM tube. The LLD establish a threshold hold for the voltage signal from the detector to define an pulse. ...
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0answers
47 views

ESP12e: analog reading not working with voltage divider

I'm trying to read from an analog sensor (a capacitive soil moisture sensor). I'm using a ESP12E, not a development board, so the ADC pin can only take 1V max. Since my sensor can output up to 3V, I ...
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0answers
39 views

Amplifying analog signal from AO of KY-038

I'm using a KY-038 for sensing sound if I connect the DO pin and set the potentiometer to the highest viable sensitivity then if I make a loud sound it detects and sends an output upwards until 1023. ...
1
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1answer
79 views

How to sense a control voltage without pulling it down?

I am working on a project in a photonics teachings lab. In the lab, we perform a demonstration for the students using a \$\mathrm{CO}_2\$ gas laser. The output of the laser is terminated in a ...
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0answers
32 views

Non Inverting Type 2 and 3 compensators

I'm looking for the topology and transfer function of a non-inverting type 2 and 3 compensators (PID controller). they are used in CC and CV feedback control in charging/Discharging circuits of ...
1
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1answer
160 views

8-bit VGA DAC Design Question

I am being driven up the wall with designing an 8-bit VGA DAC for an embedded application. Everywhere I've researched highlights the necessity for "impedance matching" the 75 ohm termination ...
1
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1answer
57 views

Quality Factor and Frequency Bandwidth in a matching network

it is known that the Quality Factor appears in the formulas for transformation of an impedance series bipole to a parallel one. A simple example is this one: Now I have three questions: 1) I have ...
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0answers
107 views

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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1answer
157 views

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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4answers
86 views

Momentary Over-Excitation Voltage Circuit

I want to control an electromagnetic brake (fail-safe brake) used along with servo motor. Microcontroller will control the trigger signal for the electromagnet coil. Electromagnet Requirements: ...
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0answers
144 views

Designing a 4053 IC robotic control circuit for interfacing with Sabertooth motor controller?

I am designing a control circuit for a robot and was recommended to use a 4053 IC to achieve analogue multiplexing. PROBLEM The Sabertooth 2x60 motor controller I am using is running in analog ...
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0answers
49 views

Emulating guitar pickup loading effects with a floating gyrator?

I'm looking to construct a high impedance buffer which emulates the loading effects of an electric guitar connected to a nonlinear, low input impedance amplifier such as the Dallas Rangemaster (...
1
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1answer
117 views

How to proove if any circuit have negative feedback?

Queries regarding this circuit I am able to say that this circuit has negative feedback but my procedure is disorganized I want a step wise procedure to identify the polarity of feedback In this ...

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