EveryCircuit - Open current source

hurz

8 years ago

Because EveryCircuit current sources are perfect and can overdrive any resistance which is in its way!

BillyT

8 years ago

So use a voltage source, not a current source. http://everycircuit.com/circuit/6674400345849856

MakotoNinja

8 years ago

@hurz - thanks for the explanation

MakotoNinja

8 years ago

@BillyT - I am working on a project that uses a LM317 as a constant current source and wanted to do some simulations before breadboarding, so I figured I could just use a current source instead of building up a constant current source using BJTs and MOSFETS.

hurz

8 years ago

Make the everycircuit ones less perfect with a parallel resistance like it is in real and it will blink for you 😉 http://everycircuit.com/circuit/5610996877230080

2ctiby

8 years ago

@Hurz... take a look at your drain terminal volts ...over 100kV lol.

hurz

8 years ago

Yes Professor 2ctiby, but it depend on the internal voltage a real current source have to buildup its current. It probably stops at 30V if you have only 30V. But as long its not clear whats available its a first step of transformation from a perfect one to a not perfect one. Or even from current source to voltage source, if you know what I mean. Im afraid you have no idea.

hurz

8 years ago

Here for Professor 2cent a more realistic current source model, but still a.guess http://everycircuit.com/circuit/5610996877230080

2ctiby

8 years ago

http://everycircuit.com/circuit/4907406609088512

hurz

8 years ago

So Mr @2cent, the original circuit was not blinking, and I have just made the perfect current source a little less perfect to demostrate what the issue is. So what is you do not understand about that?

hurz

8 years ago

Ahh, and Messy 2cent, you should read all comments to check whats the challenge is for this circuit!

hurz

8 years ago

And we can limit the voltage to any you want if you are mind reading you probably already know what the U0 is?

2ctiby

8 years ago

Variation ... http://everycircuit.com/circuit/4670193954717696

hurz

8 years ago

How is this circuit related to this thread here. You are nessing as always. But to help you, were does the 5V are coming from? How.do you make stable 5V from 10 to 70V input? Is there a chance you understand or you just continue messing?

2ctiby

8 years ago

We don't have to make a stable 5v at a Mosfet gate from the 10v to 70v source ... instead we apply a stable 5v to the gate by any way that we wish... that is one of the nice things about mosfets... the base does not connect to other parts in the way that a bjt does.... and that is why this presentation works as seen....that 5v would be altered to suit the individual Kn which we determine from our bought Mosfet... let me know if I can help you more...but you will need to cut out the know all crap because I am fed up with taking it.

hurz

8 years ago

You do not have a stable DC voltage, what is you do not understand?

2ctiby

8 years ago

In this day and age, a stable voltage for the gate is easily obtainable e.g. a battery here would suffice.. The unstable source voltage at Vds is of no consequence since the Mosfet will clamp the current as shown, regardless of any altering Vds ... that is the whole essence of why this works ... you need to think afresh from the Ohmic way when a Mosfet is working in Saturation like here.

hurz

8 years ago

Again for your stubborn mind and your continues blablabla about mosfets. "The Challenge is to make a current sink passive as constant as possible and test it against 10 to 70V" if you cant accept that you have to open your own thread and hope for any interesst in audience or continue your spam help here and fail then topic.

2ctiby

8 years ago

Do your own thing then Hurz... this schematic of mine does as seen and described ... you have no Mosfet constant current presentation. One day you may learn about Kn and Overdrive which you have not yet ever mentioned (but you never admit to having to learn anything do you). I am finished with you.

hurz

8 years ago

Do you see how stupid this way is you "argue" you seems to hate yourself for your messing

hurz

8 years ago

And I will answer you why I dont use mosfets for this and it will be new to you so listen and learn. 99% of available mosfets are not for linear analog operation, so if I need a current sink I use a.bjt this is my first choice! Mosfet are only the first choice for switching application. What you do is.just waste of time, better learn how ohms law is R V I is probably better for you.

hurz

8 years ago

You are on the way of a dead end, keep on going @2cent!