A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.

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21 views

High value ceramic capacitors?

In a project, I am using the PTN78020H power supply, and it has a recommended circuit (from the datasheet linked above) that looks like this: Now on the input, it requests a massive 4 x 4.7uF ...
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0answers
25 views

Is this circuit damaging my microcontroller?

I have a circuit which is designed to set off one of two e-matches at a given time as controlled by a microcontroller. The circuit itself functions as intended. The potential problem is that after ...
0
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1answer
80 views

Why does the capacitor takes the high-frequency current at the output of a dc-dc converter?

Lets assume that delta IL = 3A if the switching frequency es 10khz, the capacitive reactance will be Xc = 0.0397 ohm, it makes sense to asume that the current ripple will go to the capacitor, since ...
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2answers
66 views

How capacitor can be used to store data permanently in hard disk? [on hold]

How capacitor store data in hard disk if we use it? According to me when we will power up the computer capacitor will get discharged and data should have been erased? Can anyone explain, why don't get ...
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0answers
26 views

Finding the current through resistor in source free parallel RLC Circuit for t>0

My solution: Since alpha >w0, so response is overdamped. Current through inductor:$$ Il(0-)=Il(0+)=6 $$Voltage across capacitor: $$Vc(0-)=Vc(0+)=0V$$ Current through resistor: $$ Ir(t)=A1e^{s1t} + ...
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3answers
73 views

Creating a momentary low pulse with a toggle switch

I want to create a circuit with a SPST toggle switch that when flipped in one position the output signal is high and when flipped in the other the output has a momentary low pulse and then rises back ...
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2answers
42 views

How were values of Vc(0+) and i(1.5ms) found?

I get that by applying source transformation, we get a (0.1*200=20 V) source but shouldn't 0.1 A current be divided into 50 ohm and 100 ohm resistance? Also why i=0 at t=1.5ms?
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1answer
44 views

How was Vc(t) found in this source free RC circuit?

Shuldn't \$v_c(t)\$ be the same as \$10^4\space i_s\$ after \$t=0\$?
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2answers
95 views

What are the characteristics of this capacitor?

I need to replace this capacitor on the dynamo of my electric generator. Beside being 20µF, what are the important characteristics that I should look for in a replacement?
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4answers
216 views

VCC pour and decoupling capacitors on a dual layer board

I am designing a simple dual layer board which has some ICs that I have to put decoupling capacitors near them. Initially I wanted to make both top and bottom layer as ground plane and route signals ...
0
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1answer
88 views

Should I open the CRT monitor?

I have a CRT monitor which I was looking to open to acquire CRT for a project I am working on. I know its probably not the best idea but I have taken some safety measures. They are as follows: 1) ...
0
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3answers
102 views

How was this equation for finding current written?

It doesn't make any sense because at \$t\gt 0\$ the two circuits are disconnected (the left and right portion). How has \$25 i_x\over 20\$ been calculated?
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3answers
74 views

Decoupling Capacitor (High Frequency Spike)

Wondering if anyone could help me rectify my understanding of decoupling capacitors and their role in suppressing high frequency voltage spikes (particularly increases in supply voltage). Similar ...
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2answers
158 views

How does this simple contact debouncing circuit work?

I made a contact debouncing circuit using a capacitor. The main idea was to charge the capacitor, so that the bouncing on the signal would be "smoothed out". It works, but It's been a while since I ...
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1answer
38 views

Ethernet driver Circuit

I've been working on Ethernet schematics, i noticed a network of capacitor and resistors present outside the RJ45 connector. For what reasons these passive components are used? I've attached the ...
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1answer
87 views

short circuit - Time constant calculation

In calculating Tao,why can't you ignore the shorted resistors? capacitor goes to natural response when the gate shuts. \$\ v (t) = Ve^{t/T}\$ here T, is \$\ T= R_{eq}C \$ Since there is no ...
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0answers
22 views

RC Relaxation Oscillator Problems

I found a schematic for this oscillator online here and I tried it, but instead of the LED turning on and off sawtooth style, it got brighter slowly, and stayed bright without getting dimmer. What is ...
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2answers
49 views

Rule of Thumb When a Bleeder Resistor is Advisable

New to building circuits, I’m trying to develop an understanding as to when a bleeder resistor should be connected across a capacitor for safety reasons. I’ve seen several references talking about how ...
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2answers
765 views

Unwanted property of large electrolytic capacitors?

Cited article In the article above, which deals with working with high voltage, there is the statement “Measure the voltage to ensure that the capacitor has safely discharged, and be prepared for a ...
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0answers
17 views

Can I use AL- capacitor to pth05050w?

Now, I'm trying to test with PTH05050WAH module. PTH05050WAH MODULE PIP .8-3.6V 6A HORZ T/H My power source is SMPS 5V 2A adaptor and I connect directly the 5V power source of adaptor to 3 pin of ...
3
votes
3answers
135 views

Powering a microcontroller inductively from mains wire

I am in the process of making a mains power monitor using a SCT-013-000 CT clamp and an arduino mini, running on batteries. Even though I should be able to get many months of operation from two small ...
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0answers
22 views

Does the absolute sum of the elements of the imaginary part of the Y-matrix correspond to anything?

I have a simulation of a device with 4 ports (a double gated organic field-effect transistor), about which I also have some experimental data. I also made a simulation where I extracted the impedance ...
2
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1answer
58 views

Capacitor rise/fall time varying with supply voltage

While testing the capacitor voltage fall times for my board at 3 different voltage levels I see that for 6V the fall time is higher than for 18V. I checked the same on a breadboard with a ...
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2answers
55 views

How to make auto off functionality for an led lamp circuit with only transistor, capacitors, timer 555 chip?

The components I have are timer 555 chip, capacitors, and transitors. I want to create sleep functionality for a led lamp which consists of 6 leds in parallel and pnp, npn transistors. I want this ...
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1answer
55 views

Does the physical distance from electrolyc capacitor to inductor matter?

I am designing simple LC circuit (L=470uH, C=1000uF) for 12V / 12A (1 Ohm load): As you can see, I did do some soldering already (without too much or noob thinking). The capacitor and inductor ...
3
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1answer
48 views

Should I use MLCC or Tantalum capacitors near the board's power input?

My board consists of a microcontroller, some RF modules (i.e. bluetooth, wifi, etc), and a few other gadgets. It is powered by a 12V barrel adapter. I've read conflicting reports whether it's best ...
4
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5answers
149 views

Can a Tesla coil's secondary wiring overlap?

I am building a small tesla coil just as a proof-of-concept using a bug-zapper circuit. I unwound some enamel copper wire off a transformer and put it on my 12 cm length x 2 cm diameter PVC pipe and ...
7
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4answers
2k views

Why are motor capacitors huge in physical size even though their values are in uF range?

When I see some teardowns of single phase induction motors on the internet, I see their capacitors look like: Why are they that big in size compared to other caps, even though their value is in ...
3
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7answers
380 views

Role of Electrolytic Capacitors and whether they can be replaced by Film capacitors in battery operated power converters

In battery operated power converters such as motor controller ( half bridge or full bridge ) bulk capacitance is placed across Vdd and Gnd . I thought this was unnecessary since the input is DC and ...
3
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2answers
137 views

How to control over-voltage at high voltage?

Suppose we're using a voltage multiplier to charge a high-voltage capacitor (C Big in the diagram). If you significantly exceed the capacitor's voltage you'll ...
0
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4answers
110 views

Why do charge pumps use capacitors?

https://en.wikipedia.org/wiki/Charge_pump A charge pump is a kind of DC to DC converter that uses capacitors as energy-storage elements to create either a higher- or lower-voltage power ...
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1answer
63 views

How to choose MLCC cap values for power supply decoupling?

I've read that it's best to use several MLCC caps with different values to filter out as much the varied frequency noise as possible. On the output of the voltage regulator, I see some noise in the ...
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1answer
61 views

Need Capacitor for 12 volt Circuit

We are powering a circuit with a 12 Volt battery. We have a RF remote controlled Relay to turn the system on. When the system turns on the current draw is 15 Amps and then settles to 6.5 amps. The ...
3
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1answer
90 views

Sprinkle switching circuits liberally with small capacitors?

I have now read enough applied circuit diagrams that I believe I'm missing something that is obvious to those skilled in the art: Where an abstract diagram has a few components, a complete wiring ...
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3answers
75 views

Are capacitors floating power supplies?

I'm struggling with the concept of floating voltages. For a grounded supply I can connect one side to an effectively infinite ground and get full power. It may vary depending on its construction, ...
0
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1answer
49 views

Avoiding electrolytic capacitors in high-pass filters with sub-Hz cut-off

We need to design a HPF filter to AC couple a bipolar signal to a high gain amplifier. Any substantial DC left would saturate the amplifier, and thus it must be removed with the high-pass ...
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3answers
86 views

How would I go about converting a change in capacitance into a voltage?

Just starting out with electronics here as a physics student- I appreciate the help! In a simple LCR circuit with a variable capacitor, how would I go about detecting the change in capacitance and ...
0
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1answer
42 views

RC filter with an square wave input (checking my math and find my error, if it is somewhere) [duplicate]

I've this RC filter circuit (r is connect to earth on the bottom): My Vin is a square wave: With Laplace transform I derived that: $$Vout(s)=\frac{r}{r+\frac{1}{cs}}\cdot Vin(s)$$ and this ...
4
votes
2answers
136 views

Power microcontroller from super capacitor

I have a uC that works with 1.8V up to 3.3V. Current consumption is at about 20uA in sleep mode and about 12 mA in active state. The uC will enter active state for about 100 ms every minute. So I am ...
0
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1answer
58 views

RC filter with an square wave input

I've this RC filter circuit (r is connect to earth on the bottom): My Vin is a square wave: With Laplace transform I derived that: $$Vout(s)=\frac{r}{r+\frac{1}{cs}}\cdot Vin(s)$$ and this ...
0
votes
1answer
74 views

Developing an understanding of capacitor [closed]

I want to develop a better understanding of capacitors, thought about several problems and would like to check with more experienced, if my current understanding is correct and enough for solving ...
0
votes
1answer
56 views

Why Doesn't SPICE Show the Discharging of a Capacitor after Input Voltage is Removed

I have a very simple circuit that includes a capacitor meant to provide a few seconds of battery-like backup to a few LEDs when power is removed. In real life, it does exactly that. However, when I ...
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0answers
23 views

How is the standard values of resistors and capacitor defined/decided? [duplicate]

How is the standard values of resistors and capacitor defined/decided? How come some values exist but not others?
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2answers
48 views

SMPS voltage ripple

I'm using the MC34063 for my 35 VDC -> 4VDC SMPS. Here is the circuit (modelled in LTSpice): Edit: However, using a MC34063 calculator and setting Ipeak = 0.5A, L1 = 37 uH C3 = 12.5 uF Which, ...
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3answers
76 views

Capacitor Charging/Differential Equation [closed]

I study 1st year electronic engineering, and my university has a policy against posting past paper solutions. I can derive the equation in part a.) however I don't understand how to complete the 2nd ...
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votes
1answer
48 views

Controlling capacitor charge/discharge with polarity switch [closed]

I've built a little robot that goes down and up a shaft. The robot has wheels connected to a motor. The motor is connected to a switch connected to a power supply. The switch has three states - ...
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3answers
60 views

Capacitors discharging

I am a beginner at electronics so excuse my rather simplistic question. I would like to know regarding capacitors, if a capacitor is connected in a series circuit (as shown below but with a dc ...
6
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1answer
326 views

Purpose of capacitor in audio amplifier circuit

The circuit above is from a kit and is described as a Class AB audio amplifier. This is a screenshot from LTSpice. The audio input comes in at the center-left. The battery is 9V. I am trying to ...
3
votes
1answer
75 views

Is it good practice to couple the grounds of isolated supplies with capacitors

I once saw the following on an isolated dc/dc converter data sheet and have been doing it ever since with my dc/dc converters, but I wanted to ask to make sure it actually makes sense. Whenever I ...
0
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1answer
24 views

Current in circuit with switch [closed]

Switch is open in this circuit. How do I know that current IL (inductor) is 0 and voltage(Uc) of capacitor is 0 when the switch is open(t<0)? Can someone explain me this as simple as possible.