# Activity for MissMulan‭

Type On... Excerpt Status Date
Edit Post #284207 Initial revision about 23 hours ago
Question Electrolytic vs ceramic capacitors about self-resonance frequency
Which capacitors have smaller self resonance frequency?I would bet my money on electrolytic capacitors because they are usually much bigger than the ceramic capacitors however I don't know if they self inductance changes as well so here we are asking this
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Edit Post #284196 Initial revision 2 days ago
Question Capacitance of inductor
What is a typical value for capacitance of a real inductor? Does this internal capacitance exist only under AC and not DC?
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2 days ago
Comment Post #284076 @Carl please clarify?Isnt it well written,correct or well presented?
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4 days ago
Comment Post #284076 Because it is useful if someone wants to ask something relevant to the question.
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6 days ago
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7 days ago
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7 days ago
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7 days ago
Comment Post #284074 Yes oops I will edit the image.
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7 days ago
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8 days ago
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8 days ago
Edit Post #284076 Post edited:
8 days ago
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8 days ago
Edit Post #284018 Post edited:
8 days ago
Edit Post #284076 Initial revision 8 days ago
It all depends on the values of the components:If ![](https://electrical.codidact.com/uploads/i8DAX2tLRnQV7eBAtFq2icWe) the system will very slowly decay until the energy of the system reaches 0. If ![](https://electrical.codidact.com/uploads/B6ExJnRcfsKJ7YkuCPD3pLqT) the system underg...
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8 days ago
Edit Post #284074 Initial revision 8 days ago
Question Parallel RLC circuit
How to find the equation of voltage of the top common node of R1,L1 and C1 after the switch is moved? ![](https://electrical.codidact.com/uploads/TevMpbc9kY6tse4mnkjBN8Cp)
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8 days ago
Comment Post #284018 They are not homework questions and I make the images on my own , it takes plenty of time in order to contribute to this site so please respect that.
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9 days ago
Edit Post #284021 Initial revision 10 days ago
Question Inductance vs frequency
Suppose we have a sine signal applied to a inductive load. Is the inductance of the load changed if the frequency of the signal is changed?
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10 days ago
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10 days ago
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10 days ago
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10 days ago
Edit Post #284018 Initial revision 10 days ago
It all depends on the values of the components:If ![](https://electrical.codidact.com/uploads/8ym42jU8HUER4jr6uEFSL2QW) the system will very slowly decay until the energy of the system reaches 0. If ![](https://electrical.codidact.com/uploads/mL9YkvUSVf8BH1MW96VuTu2V) the system und...
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10 days ago
Edit Post #284017 Initial revision 10 days ago
Question Series RLC circuit
How to find the equation of current of the RLC circuit after the switch is moved? ![](https://electrical.codidact.com/uploads/87iESoUu42B4bQo2FKTogWHp)
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10 days ago
Comment Post #283960 @Andy aka if you read the answer a little bit below that statement (which is true) i say we have voltages due to mutual inductance-> we can say that a current exitting the doted end of the inductor can be translated to a voltage drop from the dotted end to the undotted end.
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11 days ago
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11 days ago
Comment Post #283958 I mean how inductive coupling changes the total series inductance.
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12 days ago
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12 days ago
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13 days ago
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13 days ago
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13 days ago
Edit Post #283960 Initial revision 13 days ago
When 2 inductors share the same magnetic field they become coupled and besides their self inductance they have a mutual inductance as well. For this circuit: ![](https://electrical.codidact.com/uploads/9BbSeaQgDrCoxDMhzybYnxP9) Now current entering one coil marked with a dot, produces a ...
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13 days ago
Edit Post #283958 Initial revision 13 days ago
Question Coupling of inductors
Which will be the total series inductance? ![](https://electrical.codidact.com/uploads/ChgYqAphvBFCAyPoFG2m4tAM)
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13 days ago
Comment Post #283956 It isn't dimensionless im just doing the math.
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13 days ago
Comment Post #283956 I am using a LateX editor so I cant do what you want.
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13 days ago
Comment Post #283956 The (missing)units are obvious if you read the post.
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13 days ago
Comment Post #283956 I dont see any errors maybe you can enlighten me
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13 days ago
Edit Post #283927 Post edited:
13 days ago
Edit Post #283956 Initial revision 13 days ago
Answer A: Voltage and Current of capacitor
After the switch is closed: hi The general formula for finding the voltage of the capacitor is: hi where Vf is the voltage of the inductor after infinite time,Vo is the voltage of the capacitor at the time the switch is closed Because capacitors resist any change in voltage hi ...
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13 days ago
Edit Post #283955 Initial revision 13 days ago
Question Voltage and Current of capacitor
How do I find the voltage of the capacitor and the current through the capacitor after the switch is closed?
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13 days ago
Comment Post #283926 The circuit isnt wrong but what you have suggested is a improvement of the current source/switch relationship.
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14 days ago
Comment Post #283936 1) The current source provides 0.1A to the circuit but this could well have been a typo or you may have not seen it well which is partly my fault because I didnt write it brightly enough 2)the time costant is L1/R so the t/T must have units of Ohms*seconds/Henries
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14 days ago
Comment Post #283936 Olin maybe you may want to delete this post.
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14 days ago
Comment Post #283926 What do you mean by designators exactly!?
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14 days ago
Edit Post #283927 Post edited:
14 days ago
Edit Post #283927 Initial revision 14 days ago
Answer A: Current and voltage of inductor
After the switch is closed : hi The general formula for finding the current through the inductor is this: hi where If is the current through the inductor after infinite time,Io is the current of the inductor at the time the switch is closed. Because inductors resist any change in curre...
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14 days ago
Edit Post #283926 Initial revision 14 days ago
Question Current and voltage of inductor
How do I find the current through the inductor and the voltage of the inductor after the switch is closed?
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14 days ago
Comment Post #283904 Done check it out now.
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15 days ago
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15 days ago
Comment Post #283904 You are correct I will edit
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15 days ago
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15 days ago
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15 days ago
Edit Post #283904 Initial revision 15 days ago
Answer A: Select resistor for a diode
A diode obeys the Shockley diode equation and for this circuit we have:hi hi The current through the diode must not pass a limit so for LTL-307EE we go to the datasheet to find the maximum current before the diode is destroyed: For the LTL-307EE at 20C we have 10^4 A Isat and Vth=0.026V...
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15 days ago
Edit Post #283903 Initial revision 15 days ago
Question Select resistor for a diode
Suppose we have this circuit see me How do I pick a appropriate value for the resistor R1?
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15 days ago
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15 days ago
Edit Post #283896 Initial revision 15 days ago
Question Diode like a frequency mixer
Based on this paper on Wiki a diode can be described as a frequency mixer due to the exponential relationship between current and voltage.What I don't get from which point to which point do we measure the voltage with the different frequency(or whatever)? So if we connect a oscilloscope to the cir...
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15 days ago
Edit Post #283585 Initial revision 28 days ago
Question $Q$ and $\overline{Q}$ in bistable multivibrator
In this bistable multivibrator which is $Q$ and which is $\overline{Q}$?
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28 days ago
Comment Post #283436 Suppose we have a transistor connected in series with a magnetic tunnel junction.1st case:the output voltage is low(the transistor is off) (0V)this represents the case of no charge state.2nd case:the transistor is on and the 2 layers of ferromagnetic materials which create the magnetic junction, hav...
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Comment Post #283436 @#53072iot if the charge state is 0, then we dont hav to worry about the spin state.Spintronics provide us with 3 available states unlike electronics which provides us with only 2 states.
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Edit Post #283436 Initial revision about 1 month ago
Answer A: A signal with one mode or with three or more modes
> The term "Discrete" uses to describe a signal with two modes. Wrong. Discrete means it can only take some values , not all values. I suspect by 'modes' you mean # of possible outputs. If we have a system which outputs only have 1 possible output then what would be the point of that system?...
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Edit Post #283369 Initial revision about 1 month ago
Question Tunnel current equation
The current through the tunnel diode is: hi where $I{f}$ is the current from the Shockley diode equation and $I{tunnel}$ is the tunnel current. Is there an expression for the tunnel current or is it found 'experimentally'?[]()
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Comment Post #283331 So a DC blocking capacitor to not allow any current flowing from the DC source to the AC source?
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Edit Post #283325 Initial revision about 1 month ago
Question Adding resistance to varactor circuit
If we a varactor and we want to control let's say the resonant frequency of the circuit ,in my schematic we must add R1 correct?Else we create a low resistance path for current to flow not through the varactor so the "AC circuit" gets distorted from the "DC circuit". hi So by changing the val...
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Edit Post #283249 Initial revision about 1 month ago
Answer A: 3+3 doesnt show 6
The correct 1 bit full adder is this:hi
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Edit Post #283244 Initial revision about 1 month ago
Question 3+3 doesnt show 6
I have a problem which I dont understand how to solve it.I have this 2 bit adder but when I select A1AO to be (11)2 3 and B1BO to be (11)2 3 and run it on logisim it doesnt show me 6 instead it shows me 4. Any help? hi
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Comment Post #283207 I know that.Is there a way to use the comparator(s) as 'effeciently' as possible(no loops,storage of value ) and make a simple logic digital circuit?
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Edit Post #283206 Initial revision about 1 month ago
Question Division of binary numbers logic circuit
If we want to divide two numbers I have problem implementing this logic.I am posting 1 images with 2 different steps to the solution. In example a) the most significant digits of the divident >= divisor we subtract the divisor from those 2 digits. hello In b)the most significant digits of th...
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Comment Post #283172 I cant understand which pins to connect with which pins.
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Comment Post #283170 I think multiplication can be done without bit shifting just by using full adders and taking advantage of the vertical addition of 2 binary numbers.However we are missing the point here.Is there a similar 'function' which does the same for vertical subtraction?
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Comment Post #283170 I have heard that for division of binary numbers you need to understand well subtraction so just like we can multiply 2 numbers with full adders maybe we can divide 2 numbers with full subtractors thats why I want to know how to edo subtraction using full subtractors.
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Comment Post #283172 I know how to make a full subtractor i just dont know how to connect multiple of them in order to make subtraction of 2 binary numbers with more than 1 bit
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Edit Post #283170 Initial revision about 1 month ago
Question 2 bit subtractor using full subtractor
Can we make a n-bit subtractor using full subtractors or if we want do subtract one binary from another we must use full adders and use the complement of the 2nd number to do the subtraction? I have only found examples which we use the complement of the second number and using full adders if it is...
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Edit Post #282738 Initial revision about 2 months ago
Question Electric circuit with antenna
Moderator's note: This is getting ridiculous. You keep posting these drawings that are barely legible. The scribbling is bad enough, but the uncropped images are unacceptable. The image you originally posted below was 2500 x 1667 pixels, even though the drawing occupied only a small piece of th...
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Edit Post #282733 Initial revision about 2 months ago
Question JFET equation of current
Is this equation valid only when a JFET in saturation mode , correct? because in the ohmic region the JFET acts like a voltage controlled resistor and increase in VDS increases the resistance of the JFET. Hi
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2 months ago
Edit Post #282711 Initial revision 2 months ago
Question Diodes uses in mixers
Suppose we have this circuit which is supposed to be an unbalanced frequency mixer.But how the diode generates a signal with new frequencies at the output?
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2 months ago
Comment Post #282710 An input signal can have noise and usually the noise is an AC signal so if im receiving dc signal+noise i would like to remove the noise.
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2 months ago
Edit Post #282709 Initial revision 2 months ago
Question Extract DC component of mixed signal
How can we extract a DC signal from a mixed signal?If we want to extract the AC component of a signal we can use a blocking capacitor to remove any DC offset but how do we achieve the opposite?Can we use a band-pass filter?
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2 months ago
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2 months ago
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2 months ago
Edit Post #282690 Initial revision 2 months ago
Question MOSFET differential to single ended converter intuition
How does the differential to single ended converter work? In order for the circuit to work, Q1 and Q3 must be in the saturation region and depending on the voltage inputs, one of Q2 and Q4 will be in the ohmic region and one will be in the saturation region. I understand that IQ1 is copied to (...
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2 months ago
Comment Post #282672 Yeah for you it may be easy I have tried learning MathJax and couldn't
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2 months ago
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2 months ago
Comment Post #282672 @#36396 I dont know how to use LaTeX and I used one of the online editors I found.I tried to find an online editor which didnt do that but I couldnt find one.
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2 months ago
Edit Post #282671 Initial revision 2 months ago
Question Voltage of tank circuit is invalid
In a previous question we found that for a critical damped oscillation: Hi But if we integrate to find the voltage through the capacitor: hI the integral is always a positive value which doesnt make any sense since the capacitor is being discharged. What am I doing wrong here?Help app...
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2 months ago
Comment Post #282635 Thanks I understand now/
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2 months ago
Comment Post #282635 Sorry what you write doesnt make any sense to me.From KVL Vs=Vc+Vl+IR , I=0 and Vs=0 (no battery connected to the circuit)->VC=-VL->VL=-2V.
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2 months ago
Comment Post #282635 I still dont get it VL=-VC = -2V.
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2 months ago
Comment Post #282627 But the opamp can correctly function without the capacitor,correct?
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2 months ago
Edit Post #282624 Initial revision 2 months ago
Question Capacitor in 2nd stage of opamp
Inside a op-amp after the stage where the differential signal is converted to single ended , there is further amplification of the DC signal.For AC signals there is a capacitor parallel to the transistor.Why is it there?
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2 months ago
Comment Post #282585 Ok it is ready for reopening
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2 months ago
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2 months ago
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2 months ago
Edit Post #282585 Initial revision 2 months ago
Question Critically damped oscillation issue
I have a question about this circuit:(critically damped oscillation) SeeMe For a critically damped oscillation for a series RLC circuit the equation of current has this form I(t)=D1te^(-at)+D2e^(-at) where D2 =I(0+) and D1-aD2 = dI(0+)/dt=VL/L. Due to L1 :I(0)=I(0+)=0A and by applying KV...
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2 months ago
Comment Post #282434 How are the equations derived?I didnt get it.
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3 months ago
Comment Post #282363 Yes and Vout cant become less than Vin-.How can we fix this?
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3 months ago
Comment Post #282363 Excellent answer!But I have done some experiments on falstad and every time Vin+ becomes less than Vin- Q2 is driven to saturation and if Vin+ becomes more than Vin- Q4 is driven to saturation.Is that normal?
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3 months ago
Edit Post #282361 Initial revision 3 months ago
Question Help with differential to single ended voltage converter
Hello I don't understand how this differential to single-ended voltage converter can work. What I don't understand is why we place a current mirror(a current mirror copies the current flowing through one transistor to another transistor) and how is the output voltage affected by the input volt...
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3 months ago
Edit Post #282262 Initial revision 3 months ago
Question Unexpected phase shift in results
I find the current flowing through the capacitor \begin{align} I{C1}(t)&=\dfrac{\mathrm{d}}{\mathrm{d}t}\left[V1(t)-I{C1}(t)R1\right] \\\\ {}&= \dfrac{\mathrm{d}}{\mathrm{d}t}\left[\sin(t)-I{C1}(t)\right] \end{align} and by solving this differential equation we get I{C1}(t) = \dfrac...
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3 months ago
Edit Post #282180 Initial revision 3 months ago
Question Current and voltage in AC circuits without impedance
How can we find the equation of current and voltage of a capacitor circuit if the input voltage is AC without using the impedance formula Xc = -jωC?. SeeMe We have for homework to find the equation of current of the circuit and the equation of voltage of the capacitor assuming we just connected...
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3 months ago