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

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Decoding ceramic capactior

I've done some searching and found how to decode 3 digit markings, but I'm unsure about 4 digits. I have a ceramic capacitor marked: k2ORu - 9634 I gather that the K is the tolerance, not sure about ...
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1answer
30 views

Hold-up time calculation with high capacity MLCCs

I am designing a linear voltage regulator for 5V (from 30V) at 10mA for a low cost application. Everything works out so far, but I need around 10ms hold-up time in case of an input voltage failure. ...
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2answers
122 views

Finding the voltage and charge across capacitor

Can someone help me find the voltage and charge across each of the capacitors? This is not just a simple/ parallel circuit so I am having a problem in formulating the right equation on how to find the ...
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1answer
52 views

Op-Amp difference amplifier low-pass filter

I have the following (summing, single supply) difference amplifier circuit: How can I extend this circuit to a 1st or 2nd order low pass filter, with a corner frequency at about 20kHz.
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0answers
24 views

Cycling peak load trips genset

I have an application where a cycling peak load from a 40hp motor is regularly tripping a 65Kw genset. Here are the details of the configuration: 65Kw Genset powered by a natural gas engine 40hp ...
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51 views

Solve Questions on full electrical syllabus and help me out its life [on hold]

Please solve these questions and give complete answers. Thank You
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1answer
62 views

Calculating Op-amp supply bypass caps values

Either I suck at searching or there is not a lot information about calculating values of bypass caps for opamps(I found a bunch on the topic in general). The question is, what it says in the title, ...
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2answers
54 views

Reverse biased capacitor on IC input pin

I am looking at the test circuits on the data sheet for the AN6884 VU meter IC, and I cannot understand the connection to pin 8 in the following diagram: Pin 8 accepts a positive input voltage. The ...
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2answers
63 views

Voltage across a capacitor variable of integration

I understand that something that is charged with one coulomb and has a potential difference of one volt across it will have a capacitance of one farad. \$C = \frac{q}{V}\$. I get that because current ...
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2answers
61 views

Replacing Crystal Oscillator with DDS.

In a circuit like this, can the crystal oscillator be replaced with a DDS such as a AD9850? If so can it just be dropped in or would other components have to be changed? Second question, how ...
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1answer
59 views

How does one calculate the voltage ratio V+/Vo for this circuit?

I can understand the first case above, that seems simple as I can simply measure across the ground and V+, but I am getting very confused for the second case. Is the capacitor and the resistor in ...
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2answers
73 views

How capacitors connected in series are affecting the total capacitance of the network, since there is no actual flow of electricity due to dielectric?

Can someone explain how is it possible to calculate the value of caps connected in series? I am not asking about the maths, I just try to understand how can such a network be created since there is ...
4
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1answer
146 views

Maximizing force of magnetic mass accelerator

I am planning to build a coil gun to fire small neodymium magnets out of a pipe. For this I am planning to use a large 400 Farad 2.7 Volt capacitor. I am wondering how many coils of wire I should ...
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2answers
202 views

How to properly discharge a high voltage capacitor?

I have recently blown a capacitor on my home made emp. I have got the perfect replacement which is an electrolytic capacitor, 330v, 140 micro farads. I have charged it but I want to learn how to ...
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2answers
52 views

pulse capacitors [duplicate]

I've got a Polypropylene 630V capacitor. Wikipedia says this about polypropylene in capacitors: "Very thin sheets of polypropylene are used as a dielectric within certain high-performance pulse and ...
1
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1answer
166 views

How can I fix a “singing” capacitor

There is a 332 1kv ceramic disk capacitor in a battery charger that I use on my desk. The capacitor emits a very high frequency and headache-inducing "singing" noise. I understand that this is normal ...
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0answers
65 views

capacitor value to add delay in circuit

I am using a relay to turn on/off a 12V motor. I wanted to add a delay in the circuit by adding a capacitor across the relay. I wanted to know what value of capacitor should I use to introduce a delay ...
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4answers
1k views

why is the time constant(RC) measured in seconds?

This is to fulfill my own curiosity as I haven't had much luck at finding the answer. I would be most grateful if someone could give me a solid answer or send me in the right direction. Thanks
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1answer
44 views

Modeling Capacitive Discharge Ignition (CDI) Circuit

I am trying to model a capacitive discharge circuit (see Fig. 1 below), but I'm having difficulty properly coupling the two inductors on the transformer and also estimating the energy dissipated ...
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2answers
102 views

Can a tank circuit store energy for a simple AC system?

If you take the circuit below, with the switch closed, assuming the Tank circuit is tuned to resonate at the same frequency as the source, then I would expect the tank to become charged, and the ...
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1answer
68 views

Can I use an electrolytic capacitor on UCAP?

I have a small board based on the ATmega32u4, which I'm assembling. I only have electrolytic capacitors in 1uF value sitting around. Can I use an electrolytic cap from UVCC to ground, instead of a ...
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0answers
104 views

How does this circuit with three transistors work?

I don't understand how this circuit works. Its a clap switch circuit with transistors. I would appreciate if someone could explain how the current flows through the circuit and which transistor ...
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1answer
81 views

I'm looking to create a simple circuit that will have 8 randomized “pulsing/fading” LED's

I am looking to make a simple (cheap, small spaced) circuit that will light 8 LEDs in a random order AND have a pulsing/fading in and out effect. I was originally going to program a randomized effect, ...
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2answers
157 views

What is the difference between these circuit?

Is there any difference between these circuit in Theory and action and Modeling? (two capacitors are equal).
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1answer
190 views

About the audible noise of capacitor

All dielectric materials deform under the stress of an electric field, it's called "electrostrictive effect". And some dielectrics exhibit an additional piezoelectric effect, such ceramic capacitors, ...
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0answers
81 views

Surface Mount vs Through Hole Aluminium Electrolytic Capacitors?

What are the differences between SMD and TH Aluminium Electrolytic Capacitors? Why are TH variants available with such greater lifetimes? (For example, Digi-key has SMD aluminium caps up to 10k hours, ...
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1answer
41 views

empty capacitor indicator + short pulse

circuit idea: // note -> times I specify in further text are symbolic ...
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1answer
49 views

Source of a NP 47µF 60+V capacitor for audio? [closed]

I am building a preamp which calls for a 47µF 60+V capacitor. It needs to be non-polar and being audio low ESR. (Yes, this is a 1NA217 based circuit.) The circuit requires NP caps if phantom power is ...
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2answers
85 views

Is it possible to use capacitor for isolation instead of optocoupler?

I designed a Buck converter which drives several LEDs. The PWM signal, which has a certain fixed duty cycle, is generated by a 555 timer IC. The circuit which drives the Buck MOSFET, including the ...
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1answer
54 views

Charge pump output resistance

I am designing (simulating in LTSpice and building on a breadboard) a charge pump to power my numitron tube. I need to get ~15-20 V out of 3.3 V. The circuit is as follows: simulate this ...
2
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1answer
82 views

PIC18 not working when wiring 30pf capacitors of cristal resonator to ground

I'm using pic18 with external oscillator 16MHZ 16M HZ HC-49S Crystal Oscillator with two 30PF capacitors configuration OSC = HS using breadboard, when wiring the ...
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2answers
167 views

The safety of the capacitor

I saw this material for making capacitors (http://www.capacitorfilm.com/web/enproduct.aspx?ch=64). It said capacitor with the material is very safe, does anyone know what is the principle under which ...
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0answers
43 views

How to calculate when a capacitor would explode? [duplicate]

Given a non-polar capacitor, how would I calculate at which voltage would it explode?
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1answer
46 views

Finding equivalent capacitance part II

Here's part I! They helped me a lot. But this problem is harder so if you can tell me where, if, I went wrong. When first switch is closed, the other one's opened. And in reverse. Here's solution ...
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2answers
90 views

Finding equivalent capacitance

Sorry, for the quality, someone could do this in the editor but I think you can see what's what. That is a switch in middle. How do you find capacitance when p(switch) is closed, and how when it's ...
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2answers
96 views

Why don't over damped and critically damped circuits oscillate?

The reason underdamped LRC circuits oscillate is because the energy keeps flowing between the inductor and capacitor. The energy is being constantly exchanged between the capacitor and inductor ...
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1answer
33 views

Capacitor with n electrodes

In my book it says that the capacitance in a capacitor with n electrodes is (n-1)*Co, Co is a capacitance of a two parallel plates capacitor. I know how to distribute charge when there are 3 parallel ...
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1answer
72 views

Why isn't this LM2917 circuit working to turn off a transistor?

It was suggested to me that I should post a new question (original question here: Minimal Hall effect sensor circuit to keep something off after certain RPM achieved). The below schematic is for ...
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2answers
79 views

Digital trimmer capacitor

We would like to design an FM transmitter module for Arduino boards. Therefore, we are in need of a trimmer capacitor that can be controlled digitally. Do digital trimmer capacitors exist or do you ...
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2answers
117 views

Does current flow stop when a capacitor is fully charged?

If I take a 1V battery and a 1 farad capacitor and a bulb and connect them in a circuit. Then will after the capacitor gets charged (not fully charged as that is impossible) will the bulb gradually ...
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3answers
86 views

Replacing capacitor from unworking TV with some other capatitors which has not the same value [closed]

I am repairing (trying to repair) my TV. I found 1 capacitor 25V \$1500\mu\$F which i think is bad (it has some weird shape at top) I don't have any capacitors with that value but I have some similar ...
6
votes
1answer
301 views

What is the purpose of a capacitor in the feedback path of a unity gain buffer?

First time using this site, I'm an EE student and have been studying opamps. So far in class we have only discussed 'ideal' opamps, but I saw an opamp with this layout and was wondering if anyone ...
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40 views

Switch capacitor analysis without initial condition

The figure below is described as: C1 and C2 are the pumping capacitors but at given time and conditions of clocks (VCk and VCk'), C1 is being charged while C2 pumps its stored charge to CL (load ...
24
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3answers
2k views

Why do they crimp capacitor leads?

Most manufacturers produces crimped and straight lead pairs of their capacitors which has exactly same capacitance and voltage rating. Why do they bother crimping the leads? What advantage does it ...
0
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1answer
67 views

Buffer Capacitors [duplicate]

What does a buffer do? In the given circuit,it is said that capacitors C1 and C4 act as buffer .What is their role here?Can't we just replace them with pull-down resisrors?
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4answers
1k views

555 timer: how to set values to take an hour

I'm new (and novice) in electronics. I came to seek your knowledge to see if someone can help me with a very basic circuit. It is a 555 chip, which should light a LED (for about 1/2 second) every ...
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0answers
56 views

Self tuning 125khz RFID reader

I have a RFID reader based on the EM4095 IC. I would like to make the reader self-tuning so it can handle varying inductance in the antenna due to reading tags near metal. I had thought of using a ...
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4answers
489 views

Turn a transistor on when any one of nine LEDs is on using an LM3914

I'm wanting to turn a transistor on when any LED from LED2 through LED10 are on with an LM3914 in dot mode. Basically, I want the transistor to be normally off until at least LED2 begins to light ...
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1answer
85 views

How can they manufacture a high fara capacitor (1F, 100F)?

In the theory, the capacitance of a capacitor can be calculated by formulas C = epsilon x A / d. And if we use this formula to calculate the area of a 1F capacitor(with d = 1m), the result of A is a ...
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1answer
55 views

How many pulses are required to charge the capacitor to 20V?

A series of current pulses of 10mA amplitude and 2ms duration are applied to an initially-uncharged, 5 uF capacitor. How many pulses are required to charge the capacitor to 20V? I thought of this ...