Electrical Engineering

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Shalvenay

01:09

hey there @ThePhoton

The Photon

@Shalvenay hey

7 hours later…

Bartek Banachewicz

07:47

@PlasmaHH In the meantime I've ordered a cheap step-down module which I might try to hack for my constant current needs

4 hours later…

PlasmaHH

11:35

some exception messages are just nice:

> failed: The desired capacity is bigger than 1TB. How much RAM do you have installed?

1 hour later…

Asmyldof

12:51

@PlasmaHH I quite like that. Little bit tongue in cheek. To the point. Very clear.

abdullah kahraman

PlasmaHH

13:11

@Asmyldof We have recently installed a server with 256MB of ram, so in a couple of years that error might be revised... ^^

Asmyldof

@PlasmaHH Do you mean GB?

PlasmaHH

lol, yeah

Asmyldof

Else I'd have been impressed!

PlasmaHH

( on another console I just entered an amount in MiB into a config)

2 hours later…

Gilles

14:47

Q: Why is CAS latency so hard to reduce?

I think that I need to understand how it works in order to get this. I'm asking this because I found this timelapse about the total time requiring a 128-bytes cache line. (It is in spanish but I think it's readable)

computer-architecture

Would EE.SE take this question, or is it not technical enough?

2 hours later…

The Photon

17:10

@Gilles Pretty low quality. Needs to say specifically what the graphs are measuring (I think the green bar is the part of the read time is due to "CAS latency", but I'm not sure) Also, for EE, he'd need to explain what "CAS latency" means.

2 hours later…

KyranF

18:42

anyone know the proper name for a DIN rail "component terminal" that allows mounting a through-hole resistor or capacitor?

Asmyldof

That's a whatchamacallems

KyranF

i'm looking for something like the little mount thingy with the diode in it, in this picture phoenixcontact.com/assets/images_ed/global/web_content/…

but that simple holds the component in place, and makes each leg available as a screw terminal contact

Asmyldof

@KyranF Those are prefab, not DIY

KyranF

i was on a job site recently, and we needed some pull-down resistors for a sensor interface and it the guys there had a really neat looking little DIN mount terminal thingy with a spring-contact insert for the legs of the resistor

I see phoenix contact does a bunch of pre-soldered resistors in terminals, not quite what i am lookin for.. :(

PlasmaHH

Anyone seen my lockpick set? I really need it tomorrow :/

dirac16

19:10

@ThePhoton Are you here, I have a question?

The Photon

@dirac16 sorry, just going out to lunch

PlasmaHH

@dirac16 Heisenberg says he is neither here nor there, yet he is there and here

@Gilles there is a good question waiting to come out. The reason why it is designed that way and how this is a shortcoming of the design of dram is interesting and touches ee territory, however a lot is explained in the Wikipedia article, thus a question here would need to be more specific

dirac16

19:31

@PlasmaHH I'm strongly against Heisenberg and the theory of quantum mechanics!

PlasmaHH

19:48

@dirac16 I am sure the universe cares

Gilles

@PlasmaHH thanks for the feedback, I took the liberty of citing you

dirac16

@PlasmaHH once I talked to a physicist at Berkeley. I told her a meson can "see" what it's doing but she said no particles cant see.

Though this theory is not what I support it works in many places and people can't throw it away.

PlasmaHH

20:10

@dirac16 you three should sit down and talk about what you saw

dirac16

@PlasmaHH I don't remember the question I asked her. It was a while ago. It was about some inter atomic processes. At some point I had no way other than attributing "eyes" to the particle. But she didn't like my view.

Giskard42

20:41

@dirac16 You mean a hidden variable sort of thing?

dirac16

21:03

@Giskard42 If a particle that's under measurement were magically able to tell us either it's position or it's momentum, there would have been no uncertainty thing. But since we are not able to "hear" them, we'll have to stick with the theory.

PlasmaHH

@dirac16 imho it makes most sense in an interpretation like everetts but based on the simultaneous interaction of wave functions on the fields in multiple dimensions. a bit too much for a webchat though ^^

dirac16

21:29

Here's a circuit that consists of two Wildar current sources:

Q1-Q5 and Q1-Q6 are both Widlar current sources. According to my calculations, the current of I5 and I6 have to be equal, because VT. ln(I6/I5)=(I5-I6)*R1. This equation tells that I5 and I6 have to be equal otherwise the equation doesn't have any solution.

But according to LTspice simulations, they are not equal, in fact I got I5= 1.63uA and I6=1.65uA.

The Photon

Early effect

The Early effect, named after its discoverer James M. Early, is the variation in the width of the base in a bipolar junction transistor (BJT) due to a variation in the applied base-to-collector voltage. A greater reverse bias across the collector–base junction, for example, increases the collector–base depletion width, thereby decreasing the width of the charge carrier portion of the base. == Explanation == In Figure 1, the neutral (i.e. active) base is green, and the depleted base regions are hashed light green. The neutral emitter and collector regions are dark blue and the depleted reg...

A small effect because Vce for Q6 is slightly more negative than for Q5

dirac16

21:49

@ThePhoton great, I didn't think of Early effect. The voltage at the collector of Q5 is 975mV. I connected the collector of Q6 to a separate 975mV source and this time the currents came out pretty much the same.

dirac16

22:03

@ThePhoton The currents I5 and I6 don't depend on V1 itself but if you increase V1 to, say 15V, they increase due to Early effect . That's not what I want.

The Photon

@dirac16 I don't understand. They don't depend on V1, but if you change V1, they change?

dirac16

I mean they don't depend on Vcc through a linear relation. Maybe it's proportional to log(V1)?

Also I can only say that I1=I5. I can't find an equation for I1 because I don't know what Vcb2 or Vce2 is. I know Vce2 is approx. V1-1.4. But that doesn't help.

dirac16

22:35

@ThePhoton If I were the designer of this circuit I would have put a current source I0 across the emitter of Q1 to bias Q1. That way the currents would have stayed nearly the same as I0.

Skyler

22:53

Hey guys, I'm having a hard time figuring out whether I can store persistant data on this board. I want to save a few flags and a wifi network connection info so that when I press the reset button that information (which changes while the device is powered) is preserved after the restart. The board is an esp32 clone called the WEMOS Lolin 32