A fundamental electronic component that stores energy in an electric field, commonly used in filtering applications.
-4
votes
0answers
49 views
Two phase to three phase conversion
In some places, in order to convert two phase to three phase, a capacitor bank is used which may damage the motor. How can we detect the usage of capacitor bank in a transmission line? Is there any ...
-2
votes
1answer
40 views
Fluctuation of power supply while charging capacitor [closed]
While doing capacitor charging experiment, I took the power from trolly (AC-DC), connected a potentiometer of 10k while charging, but while charging power supply is increasing, how's this possible?
7
votes
1answer
178 views
Help me modernize this audio circuit
When I was a kid, I built this circuit. You hook up a small capacitor to the test leads or maybe a couple in parallel and the speaker will output a different pitch based on the test capacitance. I ...
1
vote
2answers
75 views
Could I change a 68uF 200V 105C with a 100uF 200V 105C electrolytic capacitor in a Wii power brick? [closed]
Good day, I have a problem with my Wii just recently. Whenever I turned it on, the Wii would power up for about a minute then turn off; and after turning it again for multiple times, it would just ...
2
votes
1answer
89 views
Extracting the Most Energy From a Capacitor
I have a 5V super capacitor which I'm trying to extract the most energy from in the most efficient way possible. This capacitor is tied to the input of some regulator (which is the question of this ...
0
votes
1answer
41 views
How to test aluminum polymer capacitor for failure?
I'm not electric engineer, so maybe it is obvious, but I would like to know how do I test (in-circuit) aluminum polymer capacitor for failure? Electrolytic capacitor usually fail with easily visible ...
1
vote
0answers
63 views
Are polymer tantalum capacitors safe for use in new designs?
I want to expand this post to cover polymer tantalum caps. In my application I have an older switching regulator that outputs 24V and needs large output capacitance (220uf), so ceramic or polymer ...
0
votes
2answers
61 views
Potentiometer Ripple under load
I have the following circuit with a 10k 0.5w trim potentiometer.
simulate this circuit – Schematic created using CircuitLab
The voltage after the bridge rectifier is maintained at ~8.6 ...
0
votes
2answers
136 views
Which capacitor type is best suited for pulsed power applications?
I need advice in between MKT (metalized polyester film) and Ceramic capacitors . I am building a pulse discharging system which is required to discharge about 5KV through 10Ohm resistor in a time as ...
0
votes
2answers
59 views
How to calculate the capacity in a system of capacitors
How to calculate the capacity of the capacitor "C" given that the equivalent capacity of the system of capacitors in the figure is \$C_{eq}=9.22~\mu\mathrm{F}\$. Can you tell me also the relations ...
-1
votes
2answers
96 views
Inductors Vs. Capacitor [closed]
What are the advantages/disadvantages of using a capacitor in filter circuits instead of other passive elements?
3
votes
2answers
315 views
How long can I practically power an IC with a capacitor?
If I have, for example, an IC that draws 10mA @ 3.3V, how large of a capacitor would I need to power it for 2 minutes? 5 minutes?
I understand that using capacitors to power an IC is not the most ...
30
votes
3answers
2k views
Are tantalum capacitors safe for use in new designs?
I've heard it suggested that "solid tantalum" capacitors are dangerous and may cause fire, may fail short circuit and are fatally sensitive to even very short over voltage spikes.
Are tantalum ...
3
votes
3answers
171 views
Really odd capacitor markings
I got some capacitors about two years ago now, which I foolishly removed from their bag, and I quickly forgot their markings. I can't even figure out which kind of capacitor it is. Tantalum seems the ...
0
votes
2answers
58 views
Run a 3 Phase machine, on 240v with start & run capacitors [closed]
Being a Carpenter & Joiner, I must approach "cap in hand" and ask some proper sparkies for assistance in pointing me in the right direction please? Maybe someone could take a look at the wiring ...
1
vote
1answer
44 views
Approximation of ideal capacitors?
Capacitors are often approximated as infinite conducting plates. I find this approximation surprising since the capacitors I've seen in circuits are only a few centimetres big.
For all the ...
0
votes
2answers
62 views
Simple Capacitor Wattage Ratings
I am constructing a simple circuit to convert AC power from the wall to a 10V DC power across a load. I am fairly new at this though, so I have a question about how much power a capacitor can handle. ...
2
votes
1answer
162 views
Why Don't PC Boards Act Like Capacitors? [duplicate]
If capacitors are just two conductive components sandwiching an insulator, then why aren't all PC board, or at least their traces, considered capacitors?
2
votes
3answers
106 views
How does a dielectric alter the electric field?
My textbook is trying to explain why adding in a dielectric between two conductors causes a change in the field inside. They provide the following image:
I don't understand how the second image is ...
1
vote
3answers
421 views
Violation of conservation of energy?
Say I have a parallel plate capacitor that has a vacuum between the plates and has electric energy U. If I then add in a dielectric between the plates while the capacitor is charged, the electric ...
1
vote
0answers
61 views
Types of capacitors and their applications [closed]
Following are major types of capacitors. For each of these, what are they best known for?
I've also listed what I think I for some of these:
...
2
votes
4answers
260 views
Capacitors in series?
Capacitors in series have identical charges. We can explain how the capacitors end up with identical charge by following a chain reaction of events, in which the charging of each capacitor causes ...
4
votes
2answers
253 views
Signal LED delay mini-circuit
In making a breakout board for an SMD Bluetooth module, I realized that simply wiring LEDs to your signal lines is insufficient for a decent visual indication, as signal duration is too short to be ...
1
vote
0answers
73 views
Understanding how bypass caps work, mathematically
Assume there is a band of noises that you you want to filter with center frequency Fn. Then The complex voltage representing noise at frequency F is V_(F, T) = V(F) e^(i W(F) T), where V(F) is the ...
0
votes
1answer
48 views
What type of axial capacitor is silver with transparent ends
I am reorganising my hobby electronics workplace and have found a box of axial leaded capacitors that all look the same, apart from their size and marking. They are silver with transparent ends, no ...
-1
votes
4answers
105 views
Can capacitors conduct on both sides? [closed]
I recently learned that capacitors have two sides that are interchangeable, meaning you can hook them up to a battery in either configuration. If this is true, can you just hook both sides up to a ...
7
votes
7answers
494 views
Why aren't wires capacitors?
A parallel plate capacitor consists of two parallel conductors with opposite charges. In the above diagram, the wires are parallel and conductors so do they act as capacitor plates?
If they do, if ...
1
vote
2answers
62 views
How does a capacitive receiver work for a fox and hound set?
I have been scouring the internet trying to find this answer, I've found hints and ideas, but nothing concrete, like an actual theory of operation.
I'm making a fox and hound wire tracer for my final ...
3
votes
4answers
169 views
How to calculate equivalent capacitance to a battery?
I have a 1.25V 2Ah battery and I'm trying to calculate a equivalent capacitance with rated voltage of 2.7V for each of those batteries. This is what I did:
Work of Battery = \$1.25V * 2A * 3600s = ...
0
votes
2answers
120 views
connecting two capacitors in parallel
two capacitors are paralle connected with an open switch. both have diffrent capacity in which: $$c_1>c_2$$
and both charged with diffrent voltage
$$v_1\neq v_2$$
and now we close the switch.
...
0
votes
1answer
59 views
For a low pass filter, derivephase of the transfer function, Vout/Vin
simulate this circuit – Schematic created using CircuitLab
I have calculated the magnitude:
\$ ||H(j\omega)|| = \dfrac{1}{\sqrt{1 + {(RC\omega)}^2}} \$
5
votes
1answer
90 views
What is special about camera flash capacitors?
Capacitor manufacturers offer capacitor series that are specifically targeted on camera flash applications. For example, Rubycon has the FW series, and NCC has the PH series. These have working ...
4
votes
2answers
162 views
Need help installing a capacitor
Ok here's the problem. I have a power antenna in my car. The antenna goes up when a voltage is supplied to the voltage sensor in the antenna and goes down when the voltage is removed. I used this fact ...
3
votes
2answers
171 views
How to construct this simple circuit properly?
I am a total newbie in electronics and circuit design. I am working on a project that involves a AC motor and four 1W LEDs. I found a motor that works for me and it comes with a AC/AC power adaptor ...
1
vote
1answer
105 views
How does a series capacitor affect a square-wave on-off signal?
This question refers to the book Make electronic's experiment 18.
I have included a picture below.
...
-3
votes
2answers
85 views
Is it possible to measure a capacitors voltage while charging it? [closed]
Lets say you have a simple circuit:
simulate this circuit – Schematic created using CircuitLab
Is it possible to get any other voltage reading from this loop than source+ or source-? ...
0
votes
1answer
67 views
op-amp and capacitor 2
if i have the following circuit , what the expected behaviour of the following caps ? , it will be charge and discharge very quickly since we have a low inpedance form op-amp?
simulate this ...
1
vote
1answer
62 views
Capacitor with op-amp
if we connect a capacitor with charge = 5 volts , with buffer (op-amp) , will the capacitor will discharge it's voltage ? or because of high impedance will keep it's charge ?
simulate this ...
0
votes
1answer
148 views
How to use Boost Step-Up Converter MC34063
I am trying to use a MC34063 switching regulator to step-up 5v to 12v.
I have wired it up as shown below, I think its the same as the datasheet.
But I only get ~4 volts out.
I know the capacitors ...
0
votes
4answers
96 views
Calculating Impedance for capacitor in AC circuit with some undefined waveform
I need to set up equations for some simple AC circuit. The problem is that I dont know the formula, definition for the resistance.
I know for the 1/2*PI()*f*C, but I think this is only valid for the ...
-6
votes
1answer
84 views
Increase Amperage With Capacitors without any change in voltage [closed]
I want to know how to increase the current/amperage without changing the amount of
voltage. I found this formula:
I (t) =
Vs/R * e^-t/RC
from this ...
2
votes
2answers
169 views
What is the purpose of the capacitor in this schematics?
I am trying to understand a RTC module from Sparkfun.
I don't understand the purpose of the capacitor in this circuit.
Here are the
procduct's page and the schematics link.
Can some one please ...
-1
votes
1answer
62 views
conduction current vs displacement current across capacitor [duplicate]
Kindly help me understand the difference between conduction current and displacement current. Quick searches explain that displacement current is associated with changing electric field, frankly ...
1
vote
1answer
78 views
What does “.1M/250” mean as a capacitor rating?
I'm not very familiar with capacitor markings, and I'm trying to understand what exactly this one means. I'm guessing .1M indicates 0.1 microfarads with 20% tolerance, but I have no idea what the /250 ...
4
votes
5answers
250 views
How can a capacitor store charge whilst also passing current?
It's frequently said that capacitors store charge. Just reading through Wikipedia, I find:
Daniel Gralath was the first to combine several jars in parallel into a "battery" to increase the charge ...
1
vote
1answer
84 views
Rising Pitch Siren Electronics Circuit Explanation
Can somebody explain me how in detail what is going in this circuit? I tried it and it was working but I cannot understand how this works.
...
3
votes
1answer
80 views
How do I smooth current dips on a USB charger?
I've got a USB charger that I want to use to charge a phone. For about 35 seconds it outputs enough current for the phone to detect it and start charging, then for an instant (no equipment to read ...
-1
votes
3answers
90 views
Logical to physical implementation of voltage regualtor decoupling capacitors
For this typical LM7805 application :
simulate this circuit – Schematic created using CircuitLab
Due to bad planing when placing my components on the PCB (perfboard) I ended in the ...
4
votes
1answer
109 views
Is there a schematic symbol for a supercapacitor?
Is there a schematic symbol for a supercapacitor, as distinct from smaller polarized capacitors?
2
votes
1answer
62 views
Decoupling issue with DC Motor?
I have the following circuit :
That's basically everything, excepted a button on DC1 to turn on/off the motor, but shouldn't impact.
The problem is, I was prototyping with the DC Motor on the ...
