Electrical Engineering

MLM

00:06

why is the cost of jellybean switches, buttons, and pots so expensive :(

$2 per switch

anorton

@MLM Where are you seeing those prices?

MLM

@anorton okok, its adafruit but I have $10 credit there

coding_corgi

@anorton Me too, where,

anorton

ok. :)

MLM

@anorton where do you suggest?

coding_corgi

00:08

@MLM I have never bought from Adafruit, don't plan to either...

@MLM @anorton Do you guys ever buy from Jameco?

anorton

Well... I'm just getting started with electronics, so I don't have a preferred store yet.

:)

coding_corgi

@anorton SFE is your FAVORITE!!!

anorton

Some of the other people here who are now just lurking in the chatroom would probably know more...

I'm thinking about ordering from All Electronics, but I'm going to do some research on them first...

coding_corgi

@anorton Yes, lurking... But not everyone is from the US, @AnindoGhosh is in India, @jippie is in Holand, etc. Pretty cool that we are all talking from different states and continents, WWW you are the best!

@anorton I see some cheap prices! Good find!

anorton

:)

coding_corgi

00:14

@ThePhoton I solved the voltage regulator, the voltage regulator could only regulate up to 7.5V though the datasheet says otherwise, so instead of using a 5V reg. I am using a 3.3V reg.

@ThePhoton No heat on the (built-in) heatsink whatsoever!

@anorton How did you get started with EE?

anorton

It seems the next logical step for me to take... As a middle/high school student, I competed in robotics competitions using the LEGO and VEX kits. These were more focused on the mechanical construction/system programming, and "hid" the electrical work. I taught myself Java (to a fair extent...), and have participated in programming competitions.

So, I'm pretty comfortable with computer and robot programming, I have a nice background in physics/mechanical construction, I'm really comfortable in mathematics, so electricity seems to be the next place for me to go... :)

coding_corgi

@anorton Whoah, that is just scary, that is almost like my story!

anorton

I just took the second semester of physics for engineers, which focused on electricity and magnetism for a while. I found that fairly interesting, and got an Arduino (and have just ordered a RaspPi)... :) So, now I just have to learn a bit.

coding_corgi

@anorton Got a Pi!? How is it?

anorton

@coding_corgi It's in the mail with the soldering iron... :D

(well, sort of... the Pi is from Adafruit, and the soldering iron is from Sparkfun, but I ordered them at the same time)

coding_corgi

00:24

@anorton Ha ha! They sell them at a nearby computer store (near me), I might get one!

@anorton But where is AFI located?

anorton

I really don't know... I think it's in CA, but I have to check...

coding_corgi

@anorton SFE will come first, the are in Boulder, CO

@anorton But you never know...

anorton

Whoops... it looks like Adafruit is in NY...

I'm on the east coast, so they'll easily beat out Sparkfun...

I really want to build one of these: instructables.com/id/…

It looks so much better than all the 3rd hands out there on the market...

coding_corgi

@anorton Same, I am above you! OH!

@anorton Huh, I am betting 3 days, what did you do UPS Ground?

@anorton Whoah! that is awesome!

anorton

Ummm... whatever was cheapest... ;P

coding_corgi

00:28

@anorton Hope you didn't use USPS...

anorton

I actually think that UPS was cheaper than USPS...

(not sure, though... and it's too hard to fish around in email for the confirmation...)

David Kessner

@coding_corgi No, but I have friends that work at Sparkfun. I work at qsc.com.

coding_corgi

@DavidKessner Cool

@anorton Good

@anorton Hmmm....

coding_corgi

01:11

@ThePhoton Yo

coding_corgi

03:06

It is very sleepy here...

Anindo Ghosh

grEEtz

coding_corgi

@AnindoGhosh Yo!

@AnindoGhosh What time is it in Mumbai?

Anindo Ghosh

@coding_corgi 0840 hrs

coding_corgi

@AnindoGhosh Oh, like 00:00 through 24:00?

Anindo Ghosh

@coding_corgi yes

coding_corgi

03:11

@AnindoGhosh So 8:40 A.M.?

Anindo Ghosh

@coding_corgi yes

coding_corgi

@AnindoGhosh 11:12 P.M. Over on the other side of the globe...

@AnindoGhosh Whatcha doing?

Anindo Ghosh

@coding_corgi catching up on the 5-odd different sites I participate heavily in.

coding_corgi

@AnindoGhosh Like? SE?

Anindo Ghosh

@coding_corgi Yes, and reddit, and others.

coding_corgi

03:16

@AnindoGhosh Huh, what do you do all day? Work?

Anindo Ghosh

@coding_corgi www.anindoghosh.com

coding_corgi

@AnindoGhosh Photographer?

Anindo Ghosh

@coding_corgi Yup

@coding_corgi With degrees in electronics, and computer applications, and now working on a patent attorney degree.

@coding_corgi No USB cable has a built-in regulator. The heat would damage the cable under normal operation of the target device.

rawbrawb

04:16

@philliesws10 welcome!

@AnindoGhosh dude how are you?

Anindo Ghosh

@rawbrawb Top of the world! :-)

@rawbrawb And yourself?

@rawbrawb BTW, notice that you and I have been called out in the starred messages: Grumpy old men.

rawbrawb

@AnindoGhosh or at least close to it, it's not that far to chungmolungma (spelling is wrong) relative to me right?

@AnindoGhosh just got back from a BBQ at a neighbour, good times.

@AnindoGhosh by Who? Oh I see ...

Anindo Ghosh

@rawbrawb Kanchendzonga

rawbrawb

@AnindoGhosh in the west we know that as Kangchenjunga ...

Anindo Ghosh

04:32

@rawbrawb I know. So did we Indians till the Nepal government pointed out the incorrectness

rawbrawb

@AnindoGhosh and to my illiterate ear it probably sounds the same....

philliesws10

04:52

hello there, I added the post to my old post as you stated

rawbrawb

@philliesws10 OK, I started a new chat session but since you're here I'll just end that one.

angelatlarge

@philliesws10 If you put an @ in front of a name, you can respond to a particular person.

@philliesws10 You can also click on the funny little arrows that appea on the right edge of each message when you hover to respond to particular chatlets

rawbrawb

:9525411or type @

angelatlarge

1 min ago, by angelatlarge

@philliesws10 If you put an @ in front of a name, you can respond to a particular person.

rawbrawb

and first letter @philliesws10 and tab (I messed up there)

philliesws10

04:55

@rawbrawb So this should be in reply. Im sorry i misunderstood the chat you sent as well.

angelatlarge

@philliesws10 Most importantly, if you don't do any of those things, you will get an echo in here :)

rawbrawb

@philliesws10 no worries, it can be confusing

angelatlarge

@philliesws10 Yeah @rawbrawb can be very confusing :)

philliesws10

@rawbrawb yes im learning that quickly

rawbrawb

@angelatlarge @philliesws10 like he said, I agree I confuse myself all the time.

philliesws10

04:58

@rawbrawb im used to stackoverflow but i never use the chat

rawbrawb

@philliesws10 Just to be clear, it's entirely kosher to even ask and then answer your own question and if it contributes people will vote it up or it gets nuked.

@angelatlarge why remove that comment?

angelatlarge

@rawbrawb Or Toneyed up. I got a badge for that today :)

philliesws10

@rawbrawb yes I understand what you mean. I was just looking for someone to check the work I did to see if I worked it out correctly

rawbrawb

@philliesws10 The chat is to clear up issues, they don't want the comments cluttering up things and indeed slowly over time get nuked (or so I'm told- I've not see it myself)

angelatlarge

@rawbrawb Because it was stoopid and silly. The joke played itself out, and it was starting to stink up the room like an old Big Mac in a blue station wagon in the middle of the Sonoran desert

philliesws10

05:01

@rawbrawb very interesting ill take note in that!

rawbrawb

@philliesws10 I didn't run the calculator, but it scans OK

Anindo Ghosh

@angelatlarge Would that be a blue stink?

angelatlarge

@AnindoGhosh No, golden. The background is blue. On the outside.

philliesws10

@rawbrawb meaning the flow of my work looks correct?

rawbrawb

@angelatlarge and blue helps how? It's poetic and all but not scientifically necessary. ;)

@philliesws10 yep

angelatlarge

05:02

@rawbrawb Needed an adjective there. Could have been anything. I wanted to say something about those station wagons with the wooden sides, but I could remember the word, and couldn't be bothered to go and find it.

philliesws10

@rawbrawb Okay thank you!

rawbrawb

@philliesws10 as to the conductivity question, I was saying that it's plotted on a log/log graph so I doubt that it's entirely linear like you posted/asked.

@angelatlarge panel wagon ... ?

angelatlarge

Is that what it is called?

So...

Because it was stoopid and silly. The joke played itself out, and it was starting to stink up the room like an old Big Mac in a blue panel wagon in the middle of the Sonoran desert

@rawbrawb Still needed an adjective.

rawbrawb

@angelatlarge well tehre was the woodie surf specials too so I'm not sure.

angelatlarge

Sorry

@rawbrawb "Panel wagon" doesn't seem to be right, at least according to the google image search

Anindo Ghosh

05:05

@angelatlarge Geometric middle, or approximately "out there"?

angelatlarge

@AnindoGhosh Would you like the lattitude longtitude, and altitude (could be on a tree!)?

@AnindoGhosh More like "not close to the edge" I would think.

Anindo Ghosh

pedant, pedant, pedant-pedant-pedant (to the tune of the Pink Panther Theme).

angelatlarge

@AnindoGhosh Kinda like "you'll end up in the middle of the lake if you eat that entire pie" or "I lived in the middle of nowhere for 65 years and started to talk like Tony writes because I forgot how to cook people properly"

@AnindoGhosh Except the stress is wrong.

@AnindoGhosh For the pink panther it is weak-STRONG, weak-STRONG, but (at least I) pronounce "pedant" the opposite.

Anindo Ghosh

"Cook people properly" :-D "I do wish we could chat longer, but I'm having an old friend for dinner."

angelatlarge

@AnindoGhosh An immortal line

Maybe it is time to open a cruddy beer

Anindo Ghosh

05:10

@angelatlarge lyrical latitude

rawbrawb

@angelatlarge and were does "you'll end up in the middle of the lake if you eat that entire pie" come from?

angelatlarge

@AnindoGhosh Or altitude?

Anindo Ghosh

@angelatlarge insufficient alliteration

angelatlarge

@rawbrawb Honestly? Probably from here:

rawbrawb

signing off .... have a good one - where "one" is defined as a linker determined parameter

angelatlarge

05:16

@rawbrawb Cute

Anindo Ghosh

@rawbrawb Bye!

W5VO

I have the BOFH badge - destroy 1000 user accounts

6

Anindo Ghosh

@W5VO That must have taken an entire week, what with the help you get from your pet.

W5VO

@AnindoGhosh simple logarithmic error

rawbrawb

hey guys, I just noticed news of a record tornado ripping through oklahoma. That's @Kortuk abode isn't it? @W5VO do you know how close he might be?

W5VO

05:26

@rawbrawb I've heard from @Kortuk recently - he is OK

rawbrawb

@W5VO OK, waaaay cool!

W5VO

@rawbrawb I had the awesome experience of tuning into the news coverage of the storm as it was coming through... our county was in a tornado warning and the front was just about to hit... and then the cable company switches out the LOCAL WEATHER REPORTING for a bulletin saying "Tune to [station you were just watching] for storm updates"...... FFS!!!

jippie

05:51

good morning

angelatlarge

@jippie Hallo

@W5VO Damn you! Just wasted 30 minutes reading the BOFH files.

clabacchio

06:23

hello all!

@Kortuk hey pal, everything right out there? I've read in the news about the tornado

jippie

A new visitor in chat, we should probably explain @clabacchio how it works

;o)

abdullah kahraman

06:51

Morning!

clabacchio

07:05

@jippie sry, I no know hw tworks

@abdullahkahraman morning to you!

btw, seriously: have you heard about Oklahoma city?

our beloved Kortuk lives there as far as I know, and I'm a bit worried

Anindo Ghosh

@clabacchio We have confirmation from @W5VO that @Kortuk is OK.

jippie

@clabacchio oh?

clabacchio

@AnindoGhosh nice!

@AnindoGhosh do you know what time it was there when it happened_?

Anindo Ghosh

07:23

@clabacchio Nope, but @W5VO might, I suspect. I'm time-zone challenged enough by being nearly antipodal to you folks.

Anindo Ghosh

09:08

Anyone here at all?

abdullah kahraman

09:33

@AnindoGhosh Me :)

Anindo Ghosh

@abdullahkahraman Hiya :-)

abdullah kahraman

@AnindoGhosh Hey

Anindo Ghosh

@abdullahkahraman OK, I have a problem for which I need an innovative solution. My scope has gone for repair, and in the meanwhile I need to get a quick and trivial band-pass filter + peak detector circuit made and shipped today. Problem is, frequency range of interest is ultrasonic, else I would use a voltage follower and a speaker as my debugging tool. What might I do to check that what I build works, before sending it out?

9 volt battery, AD8044 quad op-amp circuit, 100 gain. Nothing very fancy.

abdullah kahraman

@AnindoGhosh Could you make a frequency divider and debug with your speakers again?

Anindo Ghosh

@abdullahkahraman OK, I'll think about that. Another option is actually building a comparator fed to a counter running on a 'duino. Any other ideas?

abdullah kahraman

09:38

@AnindoGhosh Ewww, I would never include digital in a scenario like this, I never trust digital stuff I create.

Anindo Ghosh

@abdullahkahraman No, I mean as an independent device, a quick and dirty diagnostic tool.

abdullah kahraman

@AnindoGhosh Yeah, if it was me, I would not trust the digital thing I would build to test

Anindo Ghosh

@abdullahkahraman OK, related note: For a bandpass, what would you do with 2 op-amps: Low-pass then high-pass, or vice versa, or something else? Fall-off need not be sharp.

abdullah kahraman

@AnindoGhosh How would I prove that my digital test thingy works?

@AnindoGhosh What is the frequency?

Anindo Ghosh

@abdullahkahraman That's relatively easy - I have ultrasonic output circuits that I use for testing stuff, those circuits are all reliable and tested.

@abdullahkahraman range from 18 KHz to 100 KHz. Upper bound can be relaxed to 50 KHz

abdullah kahraman

09:41

@AnindoGhosh so, 18kHz to 50-100kHz is OK?

Anindo Ghosh

@abdullahkahraman yep

abdullah kahraman

@AnindoGhosh How much attenuation do you need on your unwanted frequencies?

Anindo Ghosh

@abdullahkahraman like I said, fall-off can be not very sharp, but two or three octaves down (or up), I would prefer under 1% voltage left.

abdullah kahraman

@AnindoGhosh For example, -10dB for 100Hz?

Anindo Ghosh

@abdullahkahraman I work very poorly with db values, I tend to think in voltages and percentages

abdullah kahraman

09:47

@AnindoGhosh Me too :) So, you want an unwanted frequency with amplitude of 1V to drop to 1mV ?

Anindo Ghosh

@abdullahkahraman OK, and yeah I calculated, 1% voltage is -40 dB

@abdullahkahraman sengpielaudio.com/calculator-db.htm

abdullah kahraman

@AnindoGhosh Wow, this is hard.

Anindo Ghosh

@abdullahkahraman I think I'll just do a fliege bandpass filter. 2 op-amps for bandpass, 1 for virtual ground, 1 for peak detect, not too bad.

abdullah kahraman

10:02

@AnindoGhosh What is fliege bandpass filter?

Anindo Ghosh

@abdullahkahraman Wait, let me find it for you. Sec.

@abdullahkahraman instruct1.cit.cornell.edu/courses/bionb440/datasheets/… Figure 25. It is easy to stabilize, has a fixed gain of 2, as shown in that diagram. I can add gain at the peak detector.

abdullah kahraman

10:14

@rawbrawb hey!

@AnindoGhosh You have yourself a wise EE now :)

Anindo Ghosh

@abdullahkahraman :-) Excellent!

Hiya @rawbrawb

rawbrawb

@abdullahkahraman whats up?

abdullah kahraman

@rawbrawb nm, trying to get more out of a LM3485 :)

rawbrawb

@AnindoGhosh greetings

@abdullahkahraman I suggest grilling!

abdullah kahraman

@rawbrawb Been there, done that :)

rawbrawb

10:17

it releases nice epoxide flavour notes

abdullah kahraman

Anindo Ghosh

@abdullahkahraman That's not going to work - the 3485 feedback loop is not going to be stable over design currents. It's rather timing-sensitive, and every additional current amplification stage adds timing delay.

abdullah kahraman

Poor transistors

Anindo Ghosh

@abdullahkahraman It's not the transistors, you traumatized the poor controller, and it took its revenge.

abdullah kahraman

@AnindoGhosh hahahah

@AnindoGhosh I know, you have told me that before, I want to see it does not work :)

Anindo Ghosh

10:18

@abdullahkahraman On a more serious note: If they could sell it for higher current ratings, they would - they'd publish the high current adaptation as an app-note, and the device would sell for more.

abdullah kahraman

@AnindoGhosh Yeah, that is right..

Anindo Ghosh

I almost know what I want as an XMas gift. It's either a 3-D printer, or a PCB milling CNC

abdullah kahraman

@AnindoGhosh These are some expensive gifts

Anindo Ghosh

Oddly, both are essentially similar devices. Both are in the $1k-3k range (the size, speed and precision I would actually need, not the pie in the sky versions). Both are lacking a rich uncle's dying legacy.

@abdullahkahraman Thinking about it further, I might not be able to leverage a PCB miller too much: After all, I'd need to do hundreds of proto boards to get to the stage where the price becomes worthwhile - and then too, they can't do PTH so often I'd be sending out the proto boards to fabbers anyway.

@abdullahkahraman When I say PTH here, that's more about making vias than about using through-hole parts.

rawbrawb

@W5VO Would that be called a danger teaser? That's incredibly bad coordination.

Anindo Ghosh

10:24

Hey @rawbrawb what bandpass filter topology would I want to choose for a hand-fab 2-op-amp 50 gain solution, for 18 to 80 KHz band, say?

@abdullahkahraman I got my answer: vyssotski.ch/BasicsOfInstrumentation/… - the wide bandpass filter, section 5.

rawbrawb

10:42

@AnindoGhosh just a second order or will a first order do?

Anindo Ghosh

@rawbrawb From what I'm seeing the attenuation of a first order is too low.

@rawbrawb Flatness within the pass band is more important to me, though, but the two go hand in hand.

rawbrawb

I've used this before sim.okawa-denshi.jp/en/OPseikiLowkeisan.htm

Anindo Ghosh

@rawbrawb Broadly, it seems I'm going with a high pass followed by a low pass, unless you think there's some other option that will give me some advantage.

rawbrawb

here is a calculator for a multiple feedback BPF sim.okawa-denshi.jp/en/OPtazyuBakeisan.htm

abdullah kahraman

Please, ti.com/tool/filterpro..

rawbrawb

10:46

darn! I was just going to load that one!

ti.com/tool/filterpro

Anindo Ghosh

@rawbrawb Quick question: trade-off between a MFB and the high-pass low-pass combination?

rawbrawb

It works well

@AnindoGhosh MFB has fewer op-amps, tunability is reduced, with your gain you will need an additional gain section. so back to 2 op-amps.

Anindo Ghosh

@rawbrawb Yes, I have filterpro installed, I used it for some filter about a year ago. I think it';s the same version too.

@rawbrawb How's the flatness between the two?

rawbrawb

@AnindoGhosh I can't remember right now ... sorry

Anindo Ghosh

@rawbrawb ... and my other choice was a capacitive chopped filter IC, I can;t recall what they are called - I was just looking at one on the TI site a day ago.

rawbrawb

10:50

@AnindoGhosh can those handle the 100 KHz? they add in noise spurs too.

Well I have to get going, this was my middle of the night contact Europe session, back to bed for me. Ciao!

@AnindoGhosh sorry can't hang around and help you.

Anindo Ghosh

@rawbrawb The requirement is to fill an emergency: Someone needs to be able to detect signal present/absent (LED indication) in water, for an ultrasonic transducer in water. Noise spurs are not a concern, they just need to know that yes, there is a signal somewhere between 20 and 80 KHz in there, and no, the indication is not being contaminated by frequencies significantly outside that band.

@rawbrawb And yes, the one I was looking at is designed for up to 10 MHz

abdullah kahraman

11:06

@AnindoGhosh Good news, I have burnt the IC now :)

Anindo Ghosh

@abdullahkahraman You did say you have a bunch of them lying unused.

@abdullahkahraman Blown ICs are a good indicator that one is actually doing something.

@abdullahkahraman Better than just sitting at a simulator and pretending to do stuff ;-)

abdullah kahraman

@AnindoGhosh That was LM25085, I was not able to use it since it did not have an exposed pad.

@AnindoGhosh hahaha :)

@AnindoGhosh These are LM3485 I sampled 3 pcs from TI.

Anindo Ghosh

@abdullahkahraman Well, problem remains the same. The IC designers would typically have documented the best performance they can conceivably sell to a customer. Trying to exceed that is ... presumptuous.

abdullah kahraman

@AnindoGhosh hahaha, nice word :)

@AnindoGhosh I gave up.. Although I want to try increasing the base resistance on the totem-pole configuration but that could cost me one more IC..

Anyways, I've learned how to properly make double sided PCB with this..

Anindo Ghosh

11:24

@abdullahkahraman It's OK to try pushing a product rating by a little bit, but certainly not by a lot. I would generally look at a 20% overdrive on any component as worth considering (though not guaranteed to work), but any more than that is futile.

@abdullahkahraman That is driven by the basic logic of corporate strategy: If someone can sell something for 100 watt use, why would they rate it for 50 watts and lose a part of the customer base? So nobody except amateurs would underrate a device very massively.

pourjour

hi

does anybody know about FAST and SADT diagrams?

abdullah kahraman

@AnindoGhosh That is logical enough.

Anindo Ghosh

@pourjour I've used SADT analysis. Not so familiar with FAST.

pourjour

@AnindoGhosh ok, can you understand french

Anindo Ghosh

@pourjour In fact, all I know about FAST is the term. :-)

@pourjour ROTFL no. My language skills are largely in the programming language space.

abdullah kahraman

11:35

@pourjour Je sais comment parler français

Anindo Ghosh

@pourjour What exactly is the problem?

pourjour

ok that's good

I will upload a diagram after a moment

how to fill this one of the CrankShaft

abdullah kahraman

@pourjour Ne voyez-vous pas mon message?

@pourjour Je suis très bon en mathématiques

pourjour

@abdullahkahraman tu m'as dis que tu peux parler en français, c'est ça?

abdullah kahraman

@pourjour Oui, grâce à google translate

pourjour

11:42

@abdullahkahraman moi j'ai étudié le fraçais l'arabe et l'anglais

abdullah kahraman

@pourjour Oh, je sais trop arabe

pourjour

@abdullahkahraman c'est ma langue maternelle

@AnindoGhosh what do you think about this diagram?

abdullah kahraman

@pourjour ma langue maternelle est le turc

pourjour

@abdullahkahraman ah bon :)

abdullah kahraman

@pourjour il est si grand. Je peux communiquer avec vous. avec l'aide de Google Translate.

Anindo Ghosh

11:47

@pourjour Since I have no idea what the "impetus" is, I don't think about the diagram at all ;-)

pourjour

@abdullahkahraman mais la translation n'est pas toujours exacte

abdullah kahraman

@pourjour oui mais vous pouvez comprendre

pourjour

@AnindoGhosh I think it's the CrankShaft

@abdullahkahraman oui :)

Anindo Ghosh

@pourjour OK, so what about the crankshaft?

pourjour

12:11

@AnindoGhosh it's the system I'm trying to study I don't know what I must put in the case (A-0)

Anindo Ghosh

@pourjour Assuming this is the top level diagram, it has an input, an impetus (something that affects the system) and an output. What is the system itself, that you are studying?

pourjour

@AnindoGhosh it's component attached to the piston which we can find in Diesel Motor

Anindo Ghosh

OK. And what is the requirement or the problem-statement?

pourjour

@AnindoGhosh ok find it, it transform the rotation to a translation

Anindo Ghosh

@pourjour You said crank-shaft, so let me try to understand your problem. Crank-shafts use a translation motion (the piston's movement) to generate a rotation motion (the shaft rotates). Input is the existing rotation motion. Control is shaft rotation direction, coming in from above - this direction does not change so it does not get consumed.

pourjour

12:22

@AnindoGhosh but it's reversible system so we can transform rotation to translation

Anindo Ghosh

@pourjour Mechanism or impetus is the piston's translation motion, which affects the crank shaft, and thus gets consumed. Output is rotation motion at a faster or slower or same rate as the input. In other words, the piston movement has affected the rotation movement.

@pourjour Yes, that is true.

pourjour

@AnindoGhosh so if I changed the input with output is it correct

Anindo Ghosh

@pourjour Question is, is the system operating as a diesel engine's shaft, or as a generator?

@pourjour Here's where I have a problem: Since I've used SADT only while studying computer engineering, 20 years ago, I haven't ever applied it to a mechanical system. From a generic "system" point of view, I don't perceive the piston movement as an input, but as an impetus, for the engine situation. On the other hand, the piston movement is the output and the impetus is the rotation, for the generator case.

In other words, as a reversible system, I can use a rotation impetus (arrow from below) to change the translation (output), or I can use the translation as impetus to change the rotation (output). In both cases, the input and output are similar, either both translation or both rotation.

@pourjour Now, it is possible that your understanding is different. For me, impetus is what affects the input and gets consumed to change the input to the output.

pourjour

@AnindoGhosh yeah great

coding_corgi

13:03

Yo yo yo!

abdullah kahraman

@coding_corgi y0!

coding_corgi

@abdullahkahraman Yo, whatcha doing?

abdullah kahraman

@coding_corgi I have an exam for "active filter synthesis" class tomorrow, but I am doing a research about high current DC-DC converters :)

coding_corgi

@abdullahkahraman Ok, cool

See ya later!

abdullah kahraman

@coding_corgi What about you?

@coding_corgi Why? lol

user61389

13:34

Good morning

abdullah kahraman

@CamilStaps Morning?

user61389

@abdullahkahraman sssh

W5VO

@abdullahkahraman Technically

Kortuk

I am fine, for those that wondered, sorry for the worries.

6

user61389

13:50

@abdullahkahraman about your answer on the LDR question: what if there would be current flowing and a voltage drop, would it work then?

abdullah kahraman

@CamilStaps That answer is a placeholder to make the other answerers scare, until I prepare my answer. But apparently that did not work :)

user61389

@abdullahkahraman haha, okay :)

abdullah kahraman

@CamilStaps If enough current would flow, yeah, it would work.

user61389

@abdullahkahraman really? The input measures a voltage, right? What voltage would he measure then (i.e. between what points?)

abdullah kahraman

Oops, I should have made it with pull-down

user61389

13:53

@abdullahkahraman :)

abdullah kahraman

What would happen if Rin was 10k?

Then, there would be "enough" current.

user61389

Yes, then :) because the LDR would be a voltage divider with Rin. But isn't Rin way too high for that, most of the time?

abdullah kahraman

@CamilStaps You were not asking a practical question I thought, lol

user61389

14:36

@abdullahkahraman okay okay, I'll upvote your over powered answer :(

abdullah kahraman

@CamilStaps I have upvoted for you, too!

user61389

@abdullahkahraman :)

abdullah kahraman

Yaaay! Today I got 4 upvotes!

anorton

14:52

@abdullahkahraman Nice answer... :) What would happen if R2 was 0 ohms? (e.g. you had the connection to ground, but no resistor there)

user61389

@anorton eh, then you would connect the input directly to gnd, so you'd measure 0V all the time

abdullah kahraman

@anorton Then you would measure 0V

anorton

oh. I should have seen that... :)

thanks

abdullah kahraman

:)

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