Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [capacitor]

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

-3
votes
1answer
59 views

How to calculate the current flowing through a capacitor

Let's say that there is capacitor set up in a circuit: the capacitor's value : 1 F the source : 20 V How to calculate the current used by the capacitor , what equations should be used ?
0
votes
1answer
24 views

Transformer duality model with capacitor

I want to know if it is possible to transfer power through the instruments using capacitors? As you know instruments such as Marx generator actually increase the power but we aim to have sth to work ...
0
votes
2answers
43 views

Calculating the oscillator frequency

I am trying to calculate the frequency of the internal oscillator, in order to go through the design procedure listed in the datasheet. The problem is that it gives me answers that contradict the ...
0
votes
1answer
18 views

What should be the voltage rating of bootstrap capacitor?

BST_1P is the bootstrap capacitor connection pin for high-side gate driver of TAS6422. In the datasheet it is suggested that, this capacitor should have minimum rated voltage of 16 V. What is the ...
7
votes
4answers
25k views

Simple transistor & capacitor circuit question

I'm new to electronics, so what I've found to be helpful to a good learning process is examples. Now, I was studying transistors and capacitors, and as far as I could understand, a transistor acts ...
0
votes
0answers
31 views

Measuring the voltage across a capacitance with a voltage divider

I am struggling with a simple voltage divider to measure the voltage across a capacitance in a circuit. The capacitor is a 20 (or 40) uF capacitor which is charged at a certain voltage. This voltage ...
1
vote
1answer
79 views

Impedance matching a capacitor load

I am currently trying to impedance match a capacitor as a load. In detail, it is an insulating thin film grown on top of a conductive layer (grounded). We now sputtered small Pt electrodes on top and ...
3
votes
0answers
50 views

Contact a very small area (impedance matched)

In my current project, I want to apply a voltage to a capacitor (top electrode on a thin film heterostructure) very rapidly. Since capacitors have their own charging rate \$(\tau = R \cdot t = R \cdot ...
1
vote
2answers
42 views

Wouldn't Charge Flow On Power Lines Due to Capacitance

If I touch one line of an exposed power line (say 300 kV AC) and the rest of my body is freely suspended (only in contact with air), am I not forming a capacitor (to ground)? If I am, are electrons ...
2
votes
2answers
2k views

Why does this simple circuit oscillate? (Ekasi oscillator)

Why does an Ekasi oscillator oscillate? From my research, I learned that when this is first plugged in, the capacitor is charging, so the LED doesn't shine. When the capacitor reaches 12v, then the ...
1
vote
3answers
111 views

Is there any difference between voltage drop and voltage across a component?

Voltage drop across a component describes the reduction of energy when current moves through passive elements, is this the same as voltage across? What about for capacitors, technically current does ...
0
votes
0answers
46 views

Ultracapacitor doesn't charge

I am concerned about an ultracapacitor (2.7v, 3000F) that I received today. I set my power supply to 2.5v with a current limit of 1A, then connected a diode to the positive lead such that current ...
0
votes
1answer
169 views

How can i calculate forced response of \$ V_c\$ across the capacitor used transfer funtion?

$$ v= |V| u(t) \quad [V]$$ u(t) is : t<0 and 1 to t>0 \$ i_L(t) \$ = inductor current \$ v_c(t) \$= voltage capacitor This is the transfer funtion : $$ \frac{sC}{1+s^2LC} \\ w= \frac{1}{\...
6
votes
3answers
645 views

Max voltage of capacitor?

Is there a max voltage drop across a capacitor? Or does it always charge up to the same voltage as the supply? If there is a max voltage, then what would happen if the supply voltage far exceeds the ...
-4
votes
0answers
36 views
0
votes
1answer
313 views

Supercapacitor or battery with capacitor

Maybe the question that I ask is completely dumb because I am a complete noob in this, but please help. So first off, my question is that if I want to charge a 2.7v 500F supercapacitor, can I charge ...
1
vote
0answers
39 views

Non-Polarized Electrolytic Capacitor Replacement

To the best of my abilities, I'm trying to repair an Atari 800XL which was sold as "non working unit". I found a new graphics chip and it's working ok. I though that, since I had it opened up, it ...
2
votes
0answers
52 views

How to improve this microphone phantom power supply to have better SNR?

I built this power supply for my Schoeps CMT30F vintage microphones: It works, but it's not the best I can expect in terms of SNR. What would do you to ensure the SNR is the best possible? Use 0,1% ...
1
vote
3answers
77 views

How to improve an elegant design for an LED dimmer, low-powered with LDO

I am building a sunrise alarm clock. The LED is supposed to get brighter over the course of 30 minutes, then remain fully lit for another 30 minutes, then switch off. I am using a digital pin on an ...
1
vote
2answers
86 views

What is the application of capacitor between Vcc and GND [duplicate]

This is a schematic mo ATmega328P used circuit. It has paralleled two 100nF capacitors between Vcc and GND. (C8 and C9) What is the function of this two capacitors and why they are paralleled?
0
votes
0answers
21 views

Multi-stage coilgun - power source?

I am building a coil gun and am considering making it multi-stage. I want to activate them all at once and keep them on until the projectile reaches each coil, at which point they would shut off. ...
0
votes
0answers
39 views

Can this smarphone works without a protection diode? [on hold]

While I was replacing the battery, I detached a component with my fingernail. Which component is it? Image: Device name: Xiaomi Redmi5 plus You can see the missing component in the small orange ...
0
votes
1answer
47 views

Can a coil gun be made with a boost converter instead of caps?

So I’ve been starting to build a coilgun, and I find most designs either have capacitors or are just really bad. But could a high-voltage boost converter (40000v) and a momentary switch not be used to ...
-2
votes
1answer
51 views

Why 47 35V VT is getting hot? [on hold]

I have a TFT screen rated for 12V but is working with 5V in my application. My issue is that 47 35V VT is getting very hot. I can still touch it. Is this because I'm supplying 5V on an over 6V rated ...
-2
votes
1answer
51 views

How i can make transmission line from inducor and capacitor [on hold]

The questions are: How can i make an inductor using transmission line? How can i make a capacitor using transmission line?
2
votes
0answers
60 views

Home made High voltage Capacitors

Im building my own high voltage capacitors, for science, and I'm running into an issue. Im 90% sure what I'm looking at is coronal discharge but I wanted to be certain. The caps are two aluminum foil ...
2
votes
1answer
26 views

Failure Rate calculation based on manufacturing defects (capacitor)

Electronics failure rates typically follow the exponential distribution and models like Prism, Mil-Hdbk-217 or 217Plus (newer) are used to predict failure rates. We are currently in the production ...
0
votes
1answer
34 views

Modify a 1629 magic eye tube circuit to a 6E5S tube?

I've an EICO 950B capacitance tester with me. It has an aging 1629 magic eye tube. I have a bunch of 6E5S tube with me. Can you guys guide me with the modification? I know the first step to this is ...
-4
votes
0answers
65 views

Whats exactly capacitor current? [on hold]

Can anyone please explain about capacitor current? I am talking about this equation: $$I_C(t) = C\frac{dV_C(t)}{dt}$$ Like what does this mean? I have tried searching but didn't get any valid ...
0
votes
2answers
330 views

Automatic charging a capacitor to an adjustable voltage level, for impulse LED driving

simulate this circuit – Schematic created using CircuitLab UPDATE: I draw a preliminary circuit (above), after the helpful comments here. Now I use current limiting resistors both on the high ...
0
votes
0answers
25 views

I convert 120 v printer what should be the capacitor capacitance?can I use 450v 100 if? [on hold]

can u help me what should ido, I try to put 450v 100uf, its working but I can print only 30 pages.
6
votes
6answers
11k views

Why does a capacitor create a 90 degree phase shift of voltage and current?

First look at my circuit. The voltage source has a value of 5V with a phase angle of zero, and the capacitor's impedance is 5Ω. So the current is obviously 1A with a phase angle of 90°. ...
2
votes
0answers
51 views

Safety Capacitor Selection

When selecting an X2 safety capacitor what must be taken into consideration. There are only a few types of capacitance ranges and seem to be chosen based on voltage rather than capacitance. Take ...
0
votes
3answers
528 views

Capacitance of a single charged plate?

Lets say we have a single plate that has a charge of +Q on it. A plate with charge -Q is infinite distance away. Will the plate with +Q have a capacitance associated with it? Why or why not? I was ...
0
votes
0answers
19 views

Voltage Ripple in Controlled Three-Phase Rectifier

I am analyzing the controlled three-phase rectifier circuit with the RC load (R and C are in parallel). The givens are: maximum line voltage Vm, output average voltage Vo, votlage ripple delta(Vo) (in ...
1
vote
0answers
41 views

Ignition coil dilemma [closed]

I made a high voltage transformer from a pencil ignition coil, light dimmer and diy capacitor. The transformer did not make a plasma stream, and show any sign that it was working. I tested the ...
26
votes
8answers
49k views

Why put a resistor in series with signal line?

A lot of times in circuits I see a resistor placed in series in a signal line and sometimes even in series with an MCU's VDD line. Is the intention of this to smooth out noise in the line? How is this ...
0
votes
1answer
103 views

Why do XC and XL need to roughly match in an LC tank?

In an LC tank circuit, why do XC (XC1 + XC2) and XL need to be roughly similar? For example, in this Colpitts Oscillator taken from https://www.electronics-tutorials.ws/oscillator/colpitts.html, I ...
4
votes
1answer
184 views

Undescriptive capacitor and inductor values in audio-amp datasheet

I was learning about audio amplifiers and came across the STA516B IC. To my surprise, the example circuits feature some values for capacitors and inductors which seem a bit high for me. So I wanted to ...
0
votes
0answers
44 views

Finding voltage drop across a capacitor

The circuit below is a part of a continuous circuit : The question asks to find the voltage drop across the capacitor of 2 microF. The values of the resistances and currents are arbitrary. I only ...
2
votes
3answers
760 views

Function generator to test filter capacitors

I'd like to be able to see the effect that a filtering capacitor has on a voltage source with waves at different frequencies, for learning purposes. I'd like to try to calculate the correct capacitor ...
0
votes
1answer
58 views

SMD component list for capacitor

Being newbie to electronics, I'm unsure which SMD component to choose. I'm trying to build a step down voltage circuit using AMS 1117 (5 v to 3.3 v). I want to know the SMD capacitor component (...
0
votes
1answer
379 views

Choosing resistor and capacitor for active filter

I am new in designing the active filters though I designed Active low, high and bandpass and notch filter successfully (using Opamp, R and C). But these filters are not actually designed by me :-( I ...
0
votes
0answers
41 views

AT89S52 microcontroller only starts when extra 22uF capacitor touches board

I made simple code for the microcontroller that prints a simple message on the LCD once the microcontroller starts. I arranged my board so that the pull-up resistors and reset resistor (100K) and ...
2
votes
1answer
393 views

Power factor improvment c/k ratio

All power factor improvment controller has a setting c/k ratio. Their manual says it is the lowest step of capacitor bank. It controls switching threshold. But how what is its significance?
0
votes
0answers
20 views

toggling current mirror circuit

I am designing a circuit to sample the voltage from different battery cells that are serially connected (for a Battery Management System). The whole point is to measure the voltage of each battery ...
3
votes
2answers
2k views

What determines the orientation of a coupling/blocking capacitor in an amplifier circuit?

"In analog circuits, a coupling capacitor is used to connect two circuits such that only the AC signal from the first circuit can pass through to the next while DC is blocked. This technique helps to ...
1
vote
0answers
67 views

Soldering sensitive components

I am working on a project called LM317 power supply. The schematic is from the internet, and contains the regulator, filter capacitors, rectifier, potentiometer and protection diodes. I designed a ...
2
votes
1answer
52 views

Source transformation with impedance being inductor or capacitor

I found a presentation that states the following about source transformation when the impedance is capacitive/inductive: While electrical circuits books, like Nilsson's, says: If I transform the ...
0
votes
1answer
63 views

Using capacitor to protect circuit from split second power disconnects

I have a circuit powered by a 9V battery. The circuit will be subjected to significant vibrations. I want the circuit to not power off if the battery is disconnected for a second. Would a capacitor in ...