Cartoons about Cars for Kids Learn Colors with Spider Man Colored Cars for Boys
-------------------------------------------
Les 3 meilleures positions pour atteindre l'orgasme - Duration: 3:42.
For more infomation >> Les 3 meilleures positions pour atteindre l'orgasme - Duration: 3:42. -------------------------------------------
Acheter une BENTLEY Continental GT MK1 - Duration: 9:12.
For more infomation >> Acheter une BENTLEY Continental GT MK1 - Duration: 9:12. -------------------------------------------
Resultados Sorteo Loteria Miercoles 21 Febrero 2018 Loteria Nacional Panama NumerosGanadores QueJugo - Duration: 1:16.
For more infomation >> Resultados Sorteo Loteria Miercoles 21 Febrero 2018 Loteria Nacional Panama NumerosGanadores QueJugo - Duration: 1:16. -------------------------------------------
Héritage de Johnny : Nathalie Baye : "C'est à la fois le paradis et l'enfer" - Duration: 3:07.
For more infomation >> Héritage de Johnny : Nathalie Baye : "C'est à la fois le paradis et l'enfer" - Duration: 3:07. -------------------------------------------
TEST - Duration: 0:39.
CLICK
CLICK!!!
SOMANYCLICK
Fixing Cam
Gay Rainbows
IM GAY TRASLATED
WAT
GOTTAHIDEMYNUDES
WTF IS THAT NOSIE
-------------------------------------------
Cartoons about Cars for Kids Learn Colors with Spider Man Colored Cars for Boys - Duration: 10:38.
Cartoons about Cars for Kids Learn Colors with Spider Man Colored Cars for Boys
-------------------------------------------
Patancheru Powerful Ganapathi Temple || Rudraram || गणपति मंदिर || DARSHANAM LIVE || INDIAN Temples - Duration: 3:48.
For more infomation >> Patancheru Powerful Ganapathi Temple || Rudraram || गणपति मंदिर || DARSHANAM LIVE || INDIAN Temples - Duration: 3:48. -------------------------------------------
Damian Marley - Speak Life
For more infomation >> Damian Marley - Speak Life-------------------------------------------
Watch: Former HISTORY Member Jaeho Makes Solo Debut As NANO With "Forever You And I" MV - Duration: 1:30.
Watch: Former HISTORY Member Jaeho Makes Solo Debut As NANO With "Forever You And I" MV
Former HISTORY member Jaeho has made his solo debut!.
On February 20, he released his debut single Forever You and I under the name NANO.
Soompi. Display. News. English.
300x250. BTF Soompi. Mobile. English.
300x250. ATF.
The song is an R&B/Soul track with a vintage and acoustic arrangement.
NANO composed the song along with producer HSND.
Check out the music video below!.
-------------------------------------------
Man Overcomes Homophobia In Locker Room, Then Thrives In Gay Volleyball League. - Duration: 4:43.
I'm Jesse Anderson.
I'm from Asheville, North Carolina.
I've always been very active.
I've loved playing soccer and I've played all my life.
All through middle, high school - middle school, high school and college, I heard homophobic
slurs.
During middle school, we were in the locker room.
It was after a game.
One of my teammates came up to us - it was me and a couple of friends - in the locker
room and he was referring to an incident where I missed a kick and it was a crucial point
in the game.
He said, "You're a fucking faggot for missing that."
That was - that hurt a lot.
It wasn't easy to take in, it wasn't easy to deal with at the time.
So after hearing it for fifteen or so years, I was done.
I couldn't handle it anymore.
I ended up quitting and didn't participate in any additional sports activities for the
better part of four years.
When I went to college, I didn't join any competitive teams because I still felt that
I wouldn't be accepted.
So I ended up joining some intramural groups and it was still fun but it wasn't as competitive
as I would have liked it to be.
So four years later, I was hanging out with a friend.
He was one of my first gay friends in Boston.
We were sitting there chatting about things and playing video games.
He mentioned, "You should join this gay volleyball league."
I just remember thinking, is this going to be like fifteen years ago?
Is this going to be - how is this going to make me feel?
Will it be like the locker room incident?
Will it be - I don't know.
It was very scary to me.
It took some convincing but he eventually had me go.
We went.
It was right down the street from where I lived at the time and we went together.
We're walking up the stairs and we set foot in the gym.
The first thing I hear is, "Bitch, you better hit that serve!"
I was in shock.
I didn't know what to think but I felt like I actually belonged somewhere.
I kept going back consistently.
It was great to finally make more gay friends.
I didn't feel as uncomfortable with the issues I had previously because there's
people that are like me around me.
It was nerve-wracking because you're going up against really, really good people and
I had no idea what I was doing half the time, but it was great to finally feel accepted
on the court and off the court.
I started playing volleyball more competitively and I started going around the country, playing
competitive volleyball and I realized that this was going to become something very important
to me.
So as a result of joining the league, I ended up - I felt renewed confidence.
I felt like I had family in the league.
It made me want to be honest with everybody around me.
I ended up coming out to a lot of friends in the city of Boston at the time as well
as my family.
And I felt - I felt relieved.
I felt like I finally was able to truly be myself, both around them and at volleyball.
I know that there's more kids out there who've had my experience, especially in
the South and not just in the South but everywhere, and I want them to know that it's okay.
You just have to find the right group and the right organization to participate in and
you'll find family.
-------------------------------------------
TEST - Duration: 0:39.
CLICK
CLICK!!!
SOMANYCLICK
Fixing Cam
Gay Rainbows
IM GAY TRASLATED
WAT
GOTTAHIDEMYNUDES
WTF IS THAT NOSIE
-------------------------------------------
SÀI GÒN giao thông KINH DỊ như phim MỸ 27 TẾT XUÂN 2018 - CỦ CHI Bò Tơ XUÂN ĐÀO I cuộc sống sài gòn - Duration: 1:11:02.
For more infomation >> SÀI GÒN giao thông KINH DỊ như phim MỸ 27 TẾT XUÂN 2018 - CỦ CHI Bò Tơ XUÂN ĐÀO I cuộc sống sài gòn - Duration: 1:11:02. -------------------------------------------
Saints Row 4 - Temporary fear does not destroy power [MONTAGE/Interesting Moments] - Duration: 6:08.
subscribe
-------------------------------------------
Aoi Hana | English Cover | [KICKA] - Duration: 2:38.
Hey, do you ever start to wonder why we were ever born?
Hey, do you ever start to wonder why we even met?
I can't understand and it's frightening so,
Please don't you dare let go of me.
Return my grip on your hand, and pull me to you closely
So we tried our hardest, we tried to,
Escape reality
But how could we plan for everything in a made-up world so easily?
The emotions are running rampant,
A confusion stirs inside.
Embrace it, push on, push on, push on, keep advancing on!
Now upon a cracking hill,
Now underneath a rusting sky,
Yeah, we are something like blue flowers: we're just tryna thrive.
And as we come closer again we,
See the dreams that flee,
But that doesn't mean we're ready to whither up and leave!
Hey, do you ever start to wonder why we were ever born?
Hey do you ever start to wonder why we even met?
I can't understand and it's frightening so,
Please don't you dare let go of me!
Return my grip on your hand,
And pull me to you closely
Hey do you ever start to wonder why we were ever born?
Hey do you ever start to wonder why we met?
I can't understand and it's frightening so,
Please don't you dare let go of me!
Return my grip on your hand
And pull me to you closely!
-------------------------------------------
Remove artifacts in Inkscape - Duration: 3:11.
A series of shapes with coincident paths
Select a few shapes then unite them
Oops! There are "crumbs"
Let's go on
Crumbs again
Let's give it a different color
Again
There are tiny segments inside each shape
Duplicate a segment
Select both original and duplicate by fill color then…
Go to Path: Union
And the crumbs are gone
Repeat for each single segment
Now the paths are clean
-------------------------------------------
Arsenal firm favourites with bookies to beat Tottenham and Liverpool to summer transfer ● #AFC - Duration: 1:59.
Arsenal have emerged as favourites with the bookies to sign Watford midfielder Abdoulaye
Doucoure.
Doucoure is enjoying his best season in a Watford shirt, finding the back of the net
seven times and providing three assists in his 26 Premier League games.
The Frenchman has been heavily linked with a move away from Vicarage Road this summer
with a number of big clubs after his signature.
He revealed this week that the likes of Arsenal, Tottenham and Liverpool are all showing an
interest.
And bookmakers Betfair have responded by pricing the Gunners as 9/4 favourites to sign the
25-year-old when the transfer window reopens.
Liverpool are behind at odds of 10/3, with Tottenham trailing at 9/2.
Doucoure insists he is not currently paying attention to the interest from clubs as he
looks to end the season well with Watford.
Asked about interest from Arsenal, Tottenham and Liverpool, he told French outlet Telefoot:
"It's true that these clubs are interested.
But I'm at Watford for the moment and I want to finish my season well."
The lure of working under Arsene Wenger meant Arsenal would appeal to him over their north
London rivals Tottenham.
And when asked to choose between Arsenal and Spurs during a rapid fire Q&A, Doucoure replied:
"Arsenal because of Arsene Wenger."
-------------------------------------------
Rhythm Baladi -Arabic Rhythms for Belly Dance - Ritmo Baladi - Ritmos Árabes para Belly Dance - Duration: 1:25.
For more infomation >> Rhythm Baladi -Arabic Rhythms for Belly Dance - Ritmo Baladi - Ritmos Árabes para Belly Dance - Duration: 1:25. -------------------------------------------
How To Summon Bruno Mars! - Duration: 4:21.
Okay guys this video
First of all please do not try this at home
I'm gonna be something through numbers. This could go terribly wrong I
May not be here for the next video
So
This is the last video of me that you are watching I miss
I'll show you the steps to summoning Bruno Mars
But please do not try these do not
Okay
I'm doing it for the views
But please do not try this
Let's get started okay, so the first step
Is to get a plate and put 24 carrots on it no more no less
Then when you are done
Bring that to the room who will be doing the ritual in any rooms fine in this case
I'm going to be using my room. Okay, so I've got my carrots. I cannot find a plate, so I just got a bowl
Those are my carrots right there
And now the next step is you're gonna want to get the speaker of some sort or another fun
So in this case I have my google home
And what you're gonna want to do is when you're ready we're gonna play
24-karat magic, okay
24-karat magic
24 carrots this is how you're gonna be able to summon him you haven't even gonna do this split
so
What you gonna want to do is you're gonna say tell your speaker or play?
24-karat magic then what you're gonna do want to do you're gonna keep doing spins and sync Bruno Mars
We don't watch when I'm marshmallow marshmallow Mars. You know eventually you should pop up, but before all those you need to
Turn the room into total darkness
Today is today right now. It is date. It's sunset sort of
It's around five o'clock
Still what I'm gonna. Do I'm gonna turn my light switch off
It's a lot darker now now I'm going to close my blinds. Oh
No okay, how many clothes this one the other way make it even darker
Okay, this is pretty dark some light coming from there, so we can just skip this
And put this over okay
Okay kind of helps ah this should be good
Yeah, it's kind of dark. Which is good, but now we're gonna do it
It's good to have a little bit of light cuz I'll be easier to see him if he summons, so let's see this
so ready, okay, Google
Play
24-karat magic
Okay
You'll have to hold your carrots in your hand
Right you have to start eating them spin and save me no mores, so I'm gonna put one in my mouth
You know Martha no max Twitter must write one month or month
much, No Mas, No Mas No Mas
There must be must be no monster no marksman um I suppose. I must immerse was enough to the Mars
It's been a much. You know much pretty much pretty much pretty much
guys start working
Believe me. Just watch did you guys hear that oh?
my god
-------------------------------------------
DROPIL- INTRODUCING ARTHUR !! - Duration: 5:31.
What's going on get people this is Mike again with another video so yesterday when I posted my update video
And I mentioned Arthur the arbitrage bot with dropo some of you have reached out to me and asked me to make a video
Detailing what Arthur is and how you can utilize it?
so what is Arthur Arthur is an arbitrage bot its job is to find the currency on one exchange and
Find that same currency on another exchange at a higher price
So you can have the opportunity to arbitrage it and make some money that way
And if you look at it when you click on Arthur right here, it takes you to this page
And it's gonna share with you all the different percentages now. Let me break it down for you
This is Bitcoin cash if you buy it from Polonius right now at thirteen hundred sixty one dollars
And you send it to hit BTC you will sell it for fourteen hundred and thirty six dollars, and you will make a difference
Profit of seventy four dollars and 85 cents which is a total of five percent?
That's how you gotta look at it now when you click right here. You click the down arrow, it's gonna
Show you the one with the least?
Profit the up is gonna show you the one with the highest profit so if you go right now and buy Bitcoin on all
Kex for ten thousand eight hundred and sixty eight dollars send it to hit BTC
You can sell it for eleven thousand three hundred ninety three dollars, and you will make five hundred twenty-five dollars difference
Which is a four percent profit, and that's why they added the Arthur tab right here, so you can take advantage of this arbitrage?
bug and profit but in order for you to utilize it you have to have a minimum of
$50 worth of drop bulls in your account now. Let me share this with you when you click on settings. It's gonna
Take you to this page now. If you look right here. It says crypto currency, so you can select
Which crypto currency you want to arbitrage, and if you look right here?
It says exchange and you can also select which exchanges you want to utilize
So if you don't like dealing with cracking for example just uncheck it or check it if you do now another feature that they added
Is Arthur alerts and this is an amazing feature and let me tell you why because when you select email?
And you put your email address right here, and you set which
Percentage of profit you you want
Right so you can set the threshold
I want to know when a coin is ten percent higher on an exchange than another
So I can take advantage and you can set it at 20 percent and will send you an email
Instantly once it detects that feature. This is free to use as long as you bought $50 worth of drop bulls
But I have to explain something to you guys
Arbitrage is a tricky business because you're dealing with time, right?
So when you buy a coin on an exchange keep in mind that the fees the transfer time all that take into effect
Because by the time your coin gets to another exchange
Maybe that price will drop right so you have to be extremely careful
But when you're dealing with a six or seven percent or a nine percent swing
You still have a lot of time to make a lot of profit you can do this multiple times a day
Some people do it for a living. That's that's all they do now another great feature
They added is link telegram and what this does when you click link telegram. It's gonna
Ask you to enter your telegram user name once you enter your user name
You're gonna be able to see this right so when you type on your telegram once you link it slash best
it's gonna tell you a
Coin for example from bid tracks to see xio and the profits going to be twenty seven dollars
So you can do it from your telegram without logging in on their website now keep in mind guys
This is just the beginning of Arthur and they told me that
Arthur is going to have a lot more features in the future
That's down the road, and they're gonna update the roadmap and what's gonna happen is that they're gonna create a pool
You do not have to worry about buying the stock and sending to another exchange
They're gonna do it for you and give you the profit. It's going to be automated
100% they're gonna do a pool where everyone can participate
And get the right percentage depending on how much you put in in the beginning so with that being said this
Fantastic feature if you want to use it right now go right ahead
You can make some extra side money if you want to wait and you don't want to deal with it just be patient
And they're gonna create it where it's all automated for you listen Drupal is a platform. They set it up
They built it so you don't have to deal with any of it everything you do is going to be automated
They want you to set it and forget it
Like they said in their interview and Arthur is going to do that for you as well
So it's gonna be a good thing to have for the future down the line so with that being said guys
I want to remind you. I'm not a financial advisor
I don't tell you what to do you do what you want to do. Well. Thank you guys so much for watching
I appreciate you hit that subscribe button if you're not a subscriber hit that Bell right next to that subscribe button and until next time
Stay safe
-------------------------------------------
L 20:Theory of Automata,Moore Machine, Mealy Machine, Moore to mealy, Mealy to Moore in hindi - Duration: 18:56.
Like
Share
Subscribe
Comment
-------------------------------------------
Smashelorette - Duration: 43:05.
For more infomation >> Smashelorette - Duration: 43:05. -------------------------------------------
'김보름 인터뷰' 논란에 네파 "후원 계약, 연장 않고 끊겠다" - Duration: 3:39.
For more infomation >> '김보름 인터뷰' 논란에 네파 "후원 계약, 연장 않고 끊겠다" - Duration: 3:39. -------------------------------------------
YENI PREMİUM HESABIM ! Badlion - sg - Minecraft PvP /wElmin (Badlion Minecraft Survival Games #6) - Duration: 14:39.
For more infomation >> YENI PREMİUM HESABIM ! Badlion - sg - Minecraft PvP /wElmin (Badlion Minecraft Survival Games #6) - Duration: 14:39. -------------------------------------------
How to Measure the Time Constant with an Oscilloscope - Duration: 7:32.
Today we're going to look at how to rigorously measure the time constant with an oscilloscope,
as well as some of the time constant's implications for your circuits.
Measuring the time constant with an oscilloscope is surprisingly easy. All it takes is a quick
calculation and a cursor measurement. But before we get to that, why do we care
about the time constant of a circuit? The time constant is useful because it gives
us information about how our first-order circuits react to stimulus. First order circuits have
only one energy storage component – an inductor or a capacitor – and can be described using
a first-order differential equation. The TL;DR on this is that when a first order circuit
experiences a voltage step up or step down, the circuit will settle to a constant voltage.
The time constant, τ, tells us how long that settling will take.
Also, if you know the settling characteristics, then you can also determine the charge of
a capacitor or inductor at a specific point in time.
The time constant gets its name from its two key characteristics. Time, because it's
a measure of time – seconds. And constant, because the period of time it takes to settle
doesn't depend on the magnitude of the voltage step up or step down – it settles at a constant
rate. More specifically, it contributes to the charge
equation ∆ Source is the change in voltage or current
applied to the RC or RL circuit. t is the time at which we want to know the
charge on your inductor or capacitor (how long after the step up/step down)
and τ is the time constant. If we set t = τ, our formula becomes
Which gives us this: What this means is that a capacitor will charge
up to 63.2% of the source delta after one time constant.
From a settling perspective if we wait a period of one time constant, we move 63.2% closer
to our final value. After a second time constant, we move another 63.2%. Essentially it drops
to 36.8% of its starting value. Now think about this. For the period of the
second time constant, we're basically dealing with a new ∆ source value. Instead of moving
from 10V to 0V, you're now moving from 3.68V to 0V. So after the second time constant you'll
end up at 3.68 V * 36.8%, roughly 1.35V After five time constants, you'll be 99%
of the way to your final voltage – After 5 time constants people generally agree that,
for all practical purposes, the signal has settled and the inductor or capacitor is fully
charged or discharged. So, if you were to plot this out, you're
signal will look like an exponential curve. That's where the oscilloscope comes in.
For this simple RC circuit with a square wave input, we see an exponential curve. For more
on step response, check out the "Parasitic Inductance and AC Step Responses" video
which I'll link to in about a minute thirty – but you'll probably want to see this
first To measure the time constant with an oscilloscope,
you simply need to pick two reference points on the decaying portion of your signal and
see how long it takes to grow 63.2%. Here's a simple RC circuit being supplied
with a square wave going between 0 and 10 volts. For measuring the time constant, let's pick 2 V as a starting point,
which means that, after one time constant, we should end up right at 7.056 V.
We're probing the voltage across our capacitor, so it should be easy to measure the time constant
So lets turn on cursors, and to get a cleaner acquisition, let's go into "acquire" and turn on high resolution mode.
And let's bump the waveform intensity up to 100%.
Lets put our Y1 cursor at our starting voltage, which is 2 volts and
our Y2 cursor at 7.056 volts.
Now, let's move the X cursors to the intersection the waveform and the Y cursors.
Let's zoom in a little bit here to get some better horizontal accuracy for our measurements.
The distance between the X cursors is our time constant. That value that we're measuring is 104 ms..
So we can say that for this circuit our time constant is 104 ms.
To prove the time constant is actually constant,
let's do it again, but starting from 4 V.
So you can see again, we're measuring right around 104 ms.
For a more robust time constant measurement,
do this a few times with a few different captures and a few different start/stop voltages and
take the average. I'd also recommend staying towards the middle of the decay, as it's
possible to get some non-linear effects right at the beginning. An example of that is the
parasitic inductance video, linked above and in the description.
So now that we have a good idea of what our time constant is, we can compare it to our
calculated value. Before you can do that, we should probably
learn how to calculate the time constant. Without going through the math, you can do
some fancy substitutions using the formula for charge, Q = CV, and Kirchoff's law and
you end up with the elegantly simple: τ = R *C for an RC circuit, and τ = R/L
for an RL circuit. For this circuit, we are using a 1 kOhm resistor
and a 100 µF capacitor, so our calculated value is 100 ms, which his pretty darn close
to our measured value. Just for kicks, let's go a little deeper.
After one time constant, we know that the charge on the capacitor will be 638 microcoulombs
using Q=CV, and the energy stored in the capacitor will be roughly 2 milliJoules, based on W
= ½ If at some point this resistor load were to
be removed after one time constant - or there's a switch openeing up - the capacitor or inductor will throw all of that stored
energy back at your source. If you aren't careful, that can cause serious damage.
Remember, inductors resist a change in current, so if you open a switch that is providing
current to an inductor, the inductor is not going to allow that instantaneous current
change To protect against this, you can put a diode
in parallel with the inductor to allow it to discharge. This is called a freewheeling
or flyback diode. You could also build an RC snubber if you need a faster current decay.
It's not all doom and gloom, though. This charge storage can also be quite useful. This
is actually the fundamental theory behind switch mode power supplies. Take a buck converter,
for example, which is used to efficiently step down voltage.
When the switching transistor is closed, the "on state," the inductor is charging up.
When the switch is open, the off state, the inductor is powering the load.
The capacitor generally acts as a filter capacitor to help remove inherent ripple in this type
of design. This is useful because, unlike a resistive
voltage divider, you don't lose half of your energy in that other resistor.
You could also go old-school and use RC and RL circuits in conjunction with a comparator
to form an analog timer. Because the circuit's decay profile is known, you can set a threshold
level for the comparator that will cause the comparator to flip after a very specific wait
period. That's all for today, I'm Daniel Bogdanoff,
and thanks for watching! Make sure you subscribe to the Keysight Labs YouTube channel and the
Keysight Podcasts YouTube channel! If you want to dig a little deeper into inductance
and capacitance, check out the "AC step responses" video here, or watch our latest
video, which is right over my face.
-------------------------------------------
A bunch of Dummies play The Isle - Duration: 2:32:40.
For more infomation >> A bunch of Dummies play The Isle - Duration: 2:32:40. -------------------------------------------
NEW STORY MODE CHAPTER | NEW TSUNADE 2000 LIVE SUMMONS | NARUTO X BORUTO: NINJA VOLTAGE - Duration: 57:42.
For more infomation >> NEW STORY MODE CHAPTER | NEW TSUNADE 2000 LIVE SUMMONS | NARUTO X BORUTO: NINJA VOLTAGE - Duration: 57:42. -------------------------------------------
워너원 강다니엘, '복면가왕' 패널로 출격 "어제 녹화완료" - Duration: 1:44.
For more infomation >> 워너원 강다니엘, '복면가왕' 패널로 출격 "어제 녹화완료" - Duration: 1:44. -------------------------------------------
✔✔ [올림픽] 사상 첫 올림픽 경험한 태극전사들 "실패가 아닌 시작" ♥ 뉴스 속보 - Duration: 5:35.
For more infomation >> ✔✔ [올림픽] 사상 첫 올림픽 경험한 태극전사들 "실패가 아닌 시작" ♥ 뉴스 속보 - Duration: 5:35. -------------------------------------------
Final Space Premiere
For more infomation >> Final Space Premiere-------------------------------------------
Desabafo emocionante: 'Sempre sofri abuso o tempo inteiro', diz Taís Araújo - Duration: 4:51.
For more infomation >> Desabafo emocionante: 'Sempre sofri abuso o tempo inteiro', diz Taís Araújo - Duration: 4:51. -------------------------------------------
Jojo Todynho pode entrar para o 'Dança dos Famosos' na Globo - Duration: 4:11.
For more infomation >> Jojo Todynho pode entrar para o 'Dança dos Famosos' na Globo - Duration: 4:11. -------------------------------------------
How to Measure the Time Constant with an Oscilloscope - Duration: 7:32.
Today we're going to look at how to rigorously measure the time constant with an oscilloscope,
as well as some of the time constant's implications for your circuits.
Measuring the time constant with an oscilloscope is surprisingly easy. All it takes is a quick
calculation and a cursor measurement. But before we get to that, why do we care
about the time constant of a circuit? The time constant is useful because it gives
us information about how our first-order circuits react to stimulus. First order circuits have
only one energy storage component – an inductor or a capacitor – and can be described using
a first-order differential equation. The TL;DR on this is that when a first order circuit
experiences a voltage step up or step down, the circuit will settle to a constant voltage.
The time constant, τ, tells us how long that settling will take.
Also, if you know the settling characteristics, then you can also determine the charge of
a capacitor or inductor at a specific point in time.
The time constant gets its name from its two key characteristics. Time, because it's
a measure of time – seconds. And constant, because the period of time it takes to settle
doesn't depend on the magnitude of the voltage step up or step down – it settles at a constant
rate. More specifically, it contributes to the charge
equation ∆ Source is the change in voltage or current
applied to the RC or RL circuit. t is the time at which we want to know the
charge on your inductor or capacitor (how long after the step up/step down)
and τ is the time constant. If we set t = τ, our formula becomes
Which gives us this: What this means is that a capacitor will charge
up to 63.2% of the source delta after one time constant.
From a settling perspective if we wait a period of one time constant, we move 63.2% closer
to our final value. After a second time constant, we move another 63.2%. Essentially it drops
to 36.8% of its starting value. Now think about this. For the period of the
second time constant, we're basically dealing with a new ∆ source value. Instead of moving
from 10V to 0V, you're now moving from 3.68V to 0V. So after the second time constant you'll
end up at 3.68 V * 36.8%, roughly 1.35V After five time constants, you'll be 99%
of the way to your final voltage – After 5 time constants people generally agree that,
for all practical purposes, the signal has settled and the inductor or capacitor is fully
charged or discharged. So, if you were to plot this out, you're
signal will look like an exponential curve. That's where the oscilloscope comes in.
For this simple RC circuit with a square wave input, we see an exponential curve. For more
on step response, check out the "Parasitic Inductance and AC Step Responses" video
which I'll link to in about a minute thirty – but you'll probably want to see this
first To measure the time constant with an oscilloscope,
you simply need to pick two reference points on the decaying portion of your signal and
see how long it takes to grow 63.2%. Here's a simple RC circuit being supplied
with a square wave going between 0 and 10 volts. For measuring the time constant, let's pick 2 V as a starting point,
which means that, after one time constant, we should end up right at 7.056 V.
We're probing the voltage across our capacitor, so it should be easy to measure the time constant
So lets turn on cursors, and to get a cleaner acquisition, let's go into "acquire" and turn on high resolution mode.
And let's bump the waveform intensity up to 100%.
Lets put our Y1 cursor at our starting voltage, which is 2 volts and
our Y2 cursor at 7.056 volts.
Now, let's move the X cursors to the intersection the waveform and the Y cursors.
Let's zoom in a little bit here to get some better horizontal accuracy for our measurements.
The distance between the X cursors is our time constant. That value that we're measuring is 104 ms..
So we can say that for this circuit our time constant is 104 ms.
To prove the time constant is actually constant,
let's do it again, but starting from 4 V.
So you can see again, we're measuring right around 104 ms.
For a more robust time constant measurement,
do this a few times with a few different captures and a few different start/stop voltages and
take the average. I'd also recommend staying towards the middle of the decay, as it's
possible to get some non-linear effects right at the beginning. An example of that is the
parasitic inductance video, linked above and in the description.
So now that we have a good idea of what our time constant is, we can compare it to our
calculated value. Before you can do that, we should probably
learn how to calculate the time constant. Without going through the math, you can do
some fancy substitutions using the formula for charge, Q = CV, and Kirchoff's law and
you end up with the elegantly simple: τ = R *C for an RC circuit, and τ = R/L
for an RL circuit. For this circuit, we are using a 1 kOhm resistor
and a 100 µF capacitor, so our calculated value is 100 ms, which his pretty darn close
to our measured value. Just for kicks, let's go a little deeper.
After one time constant, we know that the charge on the capacitor will be 638 microcoulombs
using Q=CV, and the energy stored in the capacitor will be roughly 2 milliJoules, based on W
= ½ If at some point this resistor load were to
be removed after one time constant - or there's a switch openeing up - the capacitor or inductor will throw all of that stored
energy back at your source. If you aren't careful, that can cause serious damage.
Remember, inductors resist a change in current, so if you open a switch that is providing
current to an inductor, the inductor is not going to allow that instantaneous current
change To protect against this, you can put a diode
in parallel with the inductor to allow it to discharge. This is called a freewheeling
or flyback diode. You could also build an RC snubber if you need a faster current decay.
It's not all doom and gloom, though. This charge storage can also be quite useful. This
is actually the fundamental theory behind switch mode power supplies. Take a buck converter,
for example, which is used to efficiently step down voltage.
When the switching transistor is closed, the "on state," the inductor is charging up.
When the switch is open, the off state, the inductor is powering the load.
The capacitor generally acts as a filter capacitor to help remove inherent ripple in this type
of design. This is useful because, unlike a resistive
voltage divider, you don't lose half of your energy in that other resistor.
You could also go old-school and use RC and RL circuits in conjunction with a comparator
to form an analog timer. Because the circuit's decay profile is known, you can set a threshold
level for the comparator that will cause the comparator to flip after a very specific wait
period. That's all for today, I'm Daniel Bogdanoff,
and thanks for watching! Make sure you subscribe to the Keysight Labs YouTube channel and the
Keysight Podcasts YouTube channel! If you want to dig a little deeper into inductance
and capacitance, check out the "AC step responses" video here, or watch our latest
video, which is right over my face.
-------------------------------------------
Biscotti al tè verde matcha bimby per TM5 e TM31 - Duration: 5:41.
For more infomation >> Biscotti al tè verde matcha bimby per TM5 e TM31 - Duration: 5:41. -------------------------------------------
Mini Panqueca Fitness | Tasty Receitas - Duration: 2:26.
For more infomation >> Mini Panqueca Fitness | Tasty Receitas - Duration: 2:26. -------------------------------------------
Cartoons about Cars for Kids Learn Colors with Spider Man Colored Cars for Boys - Duration: 10:38.
Cartoons about Cars for Kids Learn Colors with Spider Man Colored Cars for Boys
No comments:
Post a Comment