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

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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 ...
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1answer
34 views

External Power Supply Grounding Scheme

The following are two possible grounding schemes for a sensitive instrument that contains high gain analog circuits and potentially noisey digital circuits: This circuit is connected to an external ...
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1answer
50 views

status equations of 2° order circuit

I have a problem with this circuit I can't write the status equation because the system that characterizes the circuit is coupled respect to derivatives of the difference of rings currents. Let ...
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1answer
26 views

BJT gain.Width of base region vs collector current

We know that in active region Ic=beta(Ib),so it means that as Ib decreases the Ic should decrease proportionally,but the early effect states that as we increase Vce the width of the base region ...
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0answers
22 views

What causes Arduino UNO to burn out with analog input of 4V and no power to board? [closed]

I have an arduino UNO R3 board and a Keyes SD card data logger shield operating on a 12Vdc wallwart supply that we are using to monitor battery voltage on a 24Vdc off-grid solar system. We collected ...
3
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2answers
89 views

OpAmp: Calculating A - MAX(B, 2V)

I require an opamp-based circuit that calculates the expression OUT = A - max(B, 2V), as shown here: There are no strict requirements on the shape or exact position of the transition, however in the ...
2
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2answers
55 views

Analog circuit for multiplying in the frequency domain [duplicate]

I have an idea I want to experiment with - doing boolean logic with analog (OFDM) signals. Each frequency component represents a different 'bit'. A key factor is performing the AND operation. I would ...
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1answer
36 views

Automatic LED lamp with sound sensor [on hold]

I have an auto light circuit with a sound sensor. The problem is when I try to simulate, this circuit does not work. Here is the circuit. I think the mistake is on the resistor is too large. then I ...
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1answer
53 views

Voltage Conversion Module

So firstly i'd like to say I'm relatively new with electrical engineering, nothing more than backyard experience. However I am a computer programmer so I can grasp the concepts fairly well. One of ...
3
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1answer
43 views

Can we determine if a filter is butterworth or chebyshev from its physical topology?

Can all analog filters be classified as Bessel, Elliptic, Butterworth or Chebyshev? Given a physical ladder topology of several stages of {L, C or LC} in {series or parallel}, is it possible to ...
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1answer
37 views

Inductor's self-resonant frequency: Do we want it to be high or low?

Inductor selection always confuses me. There is a spec for inductors as self-resonant frequency. For example, on digikey, as SR frequency of inductors increase, the price may increase or decrease. But ...
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24 views

working of operational amplifiers circuit [duplicate]

IN the Following Circuit, the opamp is neither working as buffer nor amplifier. kindly explain the working of the circuit. Its single supply opamp with 5 volt supply voltage.
3
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1answer
65 views

Reasons to use an analog temperature sensor instead of a digital one

I'm designing a microcontroller-based system that includes a thermostat. When choosing which temperature sensor to use, I noticed that analog ones have more or less the same power consumption, the ...
2
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1answer
58 views

Arduino's analog input pulling down voltage when off

I'm got a PCB manufactured, where a Arduino (Mega2560) is (via a 5V Buck converter) supplied by a 4S LiFePo4 battery which is secured by a custom BMS system. The system is measuring the voltage of the ...
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1answer
25 views

Independently toggling two series switches to multiply two pwm signals

Preface It is known that one can synthesize a signal into a train of boxcar pulses (pwm modulation), each with the same amplitude, if proper low pass filtration is applied to this pulse train before ...
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1answer
49 views

2 Layer power routing with mixed signals

I am working on a BLE Gamepad project using a module based on the Nordic NRF51822. This is the first project I have done that is more complicated then an arduino project so I am likely to make some ...
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1answer
52 views

0-5V PWM to analog 0-24VDC voltage with MOSFET

Im having trouble understanding how or if it even is possible to regulate a voltage with a MOSFET. I want to regulate an output voltage of 0-24VDC 0.5A(continuosly) with the duty cycle of a 0-5V 1kHz ...
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2answers
39 views

Thevenin Equivalent does not seem equivalent for me

The application of Thévenin theorem should give a equivalent circuit in terms of current and voltage of any linear circuit consisting of independent sources and resistances. Given this sample ...
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0answers
44 views

dc power isolation techniques

I need a circuit or a technique for DC power isolation. What i want to do is below; How can i do DC isolation between power and load? Can anyone suggest me several methods?
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3answers
54 views

Voltage divider output with analog voltmeter

I'm using a voltage divider to bring down 24V to 5V and attaching the output to an analog voltmeter gauge. So my question is should I be counting the resistance of the analog gauge into the value's of ...
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1answer
96 views

Help explain how this ac switch circuit works

Below is an ac switch circuit. COIL1_EN is used to enable or disable the switch. Does any one know how this ac switch work? I think it may be a standard design, can anyone give the related ...
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1answer
59 views

Will A Logarithmic Potentiometer Linearise A Capacitor Charge Curve?

I want to use a rising voltage on a capacitor to set more than one trigger points for events via comparators; that is when the voltage reaches a certain level, the comparator goes high. For ease I ...
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1answer
28 views

AC Analog Isolation

Please excuse my limited knowledge of electronics, my problem is I've a circuit which is driven by a variable AC signal using LabVIEW it ranges from 100Hz to 100kHz (I can lower this to 30-50kHz if ...
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2answers
83 views

I need some help with analysing this differential amp

I'm having some trouble with analysing a differential amp. The amp and its associated operating parameters are in this link (question 1) http://imgur.com/iS6fD5N What have I done so far? Well I've ...
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1answer
112 views

Are there any circuits to get output as a sum of a set of current sources?

I have 3 current sources (I1, I2 and I3) and I need to get an output of linear summation of the current of these sources. Iout = aI1+bI2+cI3 where a,b and c are gain factors (like 1 to 10 and are ...
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0answers
31 views

Help to translate jitter design constraint in a frequency synthesizer design with 4046 and 4017 ICs

I'm trying to design a frequency synthesizer with the old-school 4046 and 4017 ICs, with a scaling factor N = 1,5,7,10. The input signal is a square wave with adjustable frequency from 1 kHz to 10 ...
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1answer
60 views

op amp oscillation problem during chip measurement

I had an oscillation problem when testing my fabricated chip. As shown in these figures, the transient waveforms of the op amp outputs got severe oscillations. Ch1 and Ch2 are the two output nodes and ...
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0answers
40 views

ECG Right Leg Drive

this is a ECG circuit.aim of RLD is reducing the effect of noise.the common mode signal taken from both ends of the Rg is given back to the body as a reference. I ...
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4answers
2k views

What is the true circuit behind an opamp?

So, first year EE student, and I just learned about op-amps. I understand the ideal model, and know how to analyze them, and understand the idea behind them/the circuit that we were shown that is ...
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1answer
81 views

Why DC resistance is used in MOSFET?

With mosfets there are two resistances called DC resistance Vds/Ids and AC resistance dVds/dIds at the operating point. I am wondering about the purpose of giving the DC resistance here? Where the ...
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37 views

How to control chip select and Load DAC signals for a DAC chip?

I have a DAC7643 (Texas Instruments) - 16-Bit, Dual Voltage Output DIGITAL-TO-ANALOG CONVERTER I have been mostly unsuccessful with controlling the CS and LDAC signals. I have simulated a circuit ...
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1answer
65 views

converting an analogue signal to be viewed on a 7 segment display

How do I convert an analogue signal to a digital signal and display it on 7 segment LED's. This must be done without using any programmable micro-controllers. It's for a school project. The analogue ...
3
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1answer
412 views

What are the Differences between Analog and Digital Devices? [closed]

Consider a '555 Timer IC', Is it a Analog or Digital Device ? Or consider a more complex IC as a Microprocessor. I know the difference between a analog and Digital signal. But what is the difference ...
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43 views

Best amp to get EMG signal without noise

the EMG signal is between 5-450 HZ (mainly 10-400HZ) BUT I want the (1-35HZ) (about 5-30 uV) signal.an Example is in Circuit Description.I need help for the amp part.what is the best choise (first)to ...
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1answer
42 views

How to protect constant LED current from ripples & clamps?

I need to develope a constant current LED Driver. The product must be portable and as small as possible. So I can not use SMPS, I have use AC/DC adapter as source. This is the AC/DC adapters output: ...
4
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1answer
1k views

gain with no side effects

I want to see a signal (5-25 microvolts | 1-35HZ) on my computer.but I dont know electronics so I just have one question: I need to amplify THE signal to reach ...
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2answers
24 views

How to do level shifting signal in simulink matlab?

i want to do level shifting signal from -5..5v to 0..10v in simulink.. anyone know how to do that in simulink? thanks
4
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1answer
70 views

Is it safe to separate the power supplies for sensor, buffers, and ADC?

In the LT1054 datasheet it talks about needing a bjt to avoid pulling the VOUT positive with respect to GND (datasheet page 5 Vout (Pin5): http://www.linear.com/docs/2309). Now I am powering an ...
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3answers
317 views

Op amp with transistor in feedback

I am currently looking for a high side current sense IC. I have noticed that most of them that are without galvanic separation, are using an op amp with bjt transistor like in bellow schematics: ...
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21 views

Circuit for auto repeat switch off/on USB Data-

I recently aquired an APC UPS and connected it to my (Mac) server through USB. However, the load percentage is only updated (via pmset -g ps) when unplugging/plugging the USB cable. I found out it's ...
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1answer
50 views

How to keep/save minimum Vds value of a FET in Analog Design?

For a specific application, I need to determine minimum Vds(in other form min Rds) and need to apply it to inverting input of an opamp. I have a source comes with huge ripple like below: Before ...
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0answers
34 views

Effects of introducing offset in a current sense amplifier

I am working with the MAX9643 current sense amplifier in a configuration similar to this. I need to introduce a small offset in the output voltage. What are my options of doing this? Can I directly ...
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4answers
113 views

What analog circuit i should use to shifting a signal from -5..5v into 0..10v? [duplicate]

I want to output my circuit from -5..5v into 0..10v. My circuit generate -5..5v. What should i do to generate that signal? what analog circuit i should use? thanks
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1answer
37 views

Capacitor near analog line sensor

Is it necessary to place a capacitor near VCC even if there isn't one in the datasheet? The one I am talking about is QRE1113. ...
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2answers
33 views

Best circuit to get an array of signals with the same frequency and edge-synchronizable to a reference but individually controllable duty-cycles?

I am looking to build a circuit to control five different FET drivers individually. The input signal would be a single shot from a function generator, which should produce five output signals, with ...
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3answers
65 views

Why a transistor (MOS) changes the output current (Ids) with changes of a load resistor?

I am a newbie, and I can not understand, why current of the MOS changes if I change the resistor. Basically, why transistors so depend on load? And how I can calculate changes.. Regards, Paddy
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1answer
41 views

How to calculate the needed order of a LPF?

I am new to filters and am asked to calculated a lot of things for a passive (Butterworth and Chebyshev )LPF. The very first thing asked is to determine the needed order LPF for these specifications: ...
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2answers
49 views

Analog to digital conversion with variable VCC

I would like to build a circuit of a microcontroller reading an analog accelerometer, without the use of a voltage regulator. The problem would be that the battery's voltage will gradually decrease ...
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3answers
65 views

Changing the value of capacitor

What is the effects of replacing signed capacitors with 4uF ones related to Emi Filter performance (Electromagnetic compatibility issues). We observed that the time with 4uF ones keeps longer (power ...
0
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1answer
39 views

How to evaluate equivalent 'samples per second' from Time base value?

The following is from Tek DSO manual about the Time base and sample rates. When i turn the knob further, i am able to read values like M 100ms or M 250ms. What woud these evaluate to in terms of ...