How do I delay current in a circuit

[eddie90]

Ok so I am placing my order today since I just got paid but I have one more question, hopefully you have time to answer it.

I want to go ahead and throw in some capacitors into my order while I'm at it.
What kind of capacitors should I use though? On this page there are a lot of different categories, I'm not sure which one to use.

http://www.digikey.com/catalog/en/category/passives/capacitors/11572

I see Tantalum, Aluminum Electrolytic, Mica and PTFE and a bunch of other ones.

And I know I have to play with the Resistor and Capacitor values but do you have an idea of what range of capacitance I will be using? I want to get a few of them now to play with and if I end up needing other ones I can always stop at radio shack.

As for the voltage of the capacitors I think anything that is rated for 25 to 35 V should be fine right?

Thanks again!

 

[yungman]

OK, I don't know the exact threshold of the CMOS gate. Let's give an example and assume the threshold is abouty 60% of the supply voltage. Then we can use time constant $\tau=RC$.

Say I set R=200K, and $\tau\;$ = 10mS $\Rightarrow\; C=\frac {\tau}{200K}$. So C is about 50nF. I would get a 100K resistor and a 250K trim pot and put them in series so you get from 100K to 350K. Get a bigger resistor like 300K also just in case the 10mS is not enough. Mica is good. Get one of 47000pF( 47nF) and use trim pot to get your right delay.

Find out the threshold of the gate and use the formula to adjust the value. But you don't need to buy a lot of caps, just use resistor and trim pots to land you onto the correct delay.

 

[eddie90]

Oh that's smart, I do have a few trimmers laying around.

Ok I'm a lot clearer now on what to get, I can't find any caps under Mica that are 47000pF though? The highest I found was 10000pf?

Are you sure its 47000?

 

[yungman]

Oh that's smart, I do have a few trimmers laying around.

Ok I'm a lot clearer now on what to get, I can't find any caps under Mica that are 47000pF though? The highest I found was 10000pf?

Are you sure its 47000?

The Mylar will do. Yes, you can verify with the calculation also. I am too old to insist I am right particular after the NAND NOR thingy!

 

[eddie90]

The Mylar will do. Yes, you can verify with the calculation also. I am too old to insist I am right particular after the NAND NOR thingy!

Lol that's funny.

Anyway I made my order earlier today, can't wait for the stuff to get here!

If I may ask, how do you know so much(I looked at some of your other posts)?
I'm guessing you have a degree in EE right?

 

[yungman]

Lol that's funny.

Anyway I made my order earlier today, can't wait for the stuff to get here!

If I may ask, how do you know so much(I looked at some of your other posts)?
I'm guessing you have a degree in EE right?

Thanks for the compliment.
I have been an EE for like 30 years. I never got an EE degree. Electronics is my passion and I have been studying very hard. In fact I spent the last 8 or 9 years studying like 3 hours a day 5 to 6 days a week in electronics....After I retired 6 year ago! I have to say in my almost 60 years, electronics is my number one passion.

 

[eddie90]

Thanks for the compliment.
I have been an EE for like 30 years. I never got an EE degree. Electronics is my passion and I have been studying very hard. In fact I spent the last 8 or 9 years studying like 3 hours a day 5 to 6 days a week in electronics....After I retired 6 year ago! I have to say in my almost 60 years, electronics is my number one passion.

Thats awesome, what kind of jobs have you had in the field? Let me know if I'm being too nosey btw. I'm just curious.

Also, I just went back to school and I'm working on completing my GEs so I can start an Electrical with Computer Engineering program. In your opinion, what math subjects are important when it comes to EE? I want to start refreshing my memory on math I may have lost practice in and maybe start reviewing some of the important subjects I will need in the future. I'm guessing Calculus is on of them right?

Thanks, and sorry if I'm asking a lot of questions

 

[yungman]

Thats awesome, what kind of jobs have you had in the field? Let me know if I'm being too nosey btw. I'm just curious.

Also, I just went back to school and I'm working on completing my GEs so I can start an Electrical with Computer Engineering program. In your opinion, what math subjects are important when it comes to EE? I want to start refreshing my memory on math I may have lost practice in and maybe start reviewing some of the important subjects I will need in the future. I'm guessing Calculus is on of them right?
Thanks, and sorry if I'm asking a lot of questions

Depends on how far you want to go. If you want an AA degree, math is not as important. But if your goal is BSEE, math is the most important thing for EE. The electronics part is really not that hard. But when you study the upper division topics, books are written and explained in Calculus, so you can't even understand the book without knowing Calculus. Particular in electromagentics, Multi Variable Calculus ( Cal III in most schools) was party developed to give an easier explanation of Maxwell's equations., there is no simpler way to explain this topic...at least not that I know of. It is the language of science, like English for other subjects.

Calculus is important when you study EE, not exactly important in most of the real job. But it is so important that I actually stop studying EE and spent 2 years studying Calculus.

I learn this from experience, Before I even became an engineer, I had only 1 1/2 semester of Calculus from college. I studied on my own, but for years when I tried to study more advance subject like RF, Feedback control and EM, I kept running into walls. I tried to find books that are simpler, explaining in English, I couldn't find any good ones. Just 6 years ago after I retired, I decided to stop studying electronics and spent 2 years studying Calculus, Ordinary Differential Equation and I even studied Partial Differential Equation because I really want to study electromagnetics. I can tell you, I look at electronics in a different light.

It is a requirement for BSEE to complete Cal I to III and ODE. But you can get away with just Cal I to III. With good math background, you'll find it is much easier to read and understand the textbooks in EE. Electronics is the easy part, the math is the challenge, and you cannot move beyond certain point if you don't have enough math background. If you find a book that claim to cover a difficult subject like RF and EM without using calculus, watch out. I have over 7 books on EM and over 10 books in RF, it just don't work without Calculus.

 

[eddie90]

Yea I want to go for a BS. I sort of knew Calculus was important but I didnt know it was That, important. But it does make sense, many times when I've tried learning about subjects in electronics I've gotten completely stuck because all I see are math(Calculus I'm guessing) symbols.

I'm about to start reading a book I recently bought online just because of all the good reviews it has.
https://www.amazon.com/dp/096278155X/?tag=pfamazon01-20

I read a couple other books by this guy in the past that really helped me understand certain math/electronics subjects. Do you have any good calculus book recommendations for someone who is new to the subject?

 

[yungman]

I got a lot of Calculus book. Buy used one on Amazon particular the early editions really cheap. Not all books are equal. I am a self studier, I don't have an instructor to ask question. So I get a bunch of cheap used books to study, when ever I have a question I cannot understand from one book, I always manage to find better answer from another book.

I found the best book I ever studied in this subject is Calculus by Howard Anton, Irl Bivens and Stephen Davis. I tried to look for the 7th or the 8th edition used for you on Amazon and I can't find it now. It was dirt cheap a year or two ago. It is not easy, but again, just because the book looks easy don't mean it is good. I was fooled to choose the book by Sherman Stein because it looked easiest. But that was a disaster when I reach muli variable. It tried to be too simple that it starting to miss the point and confused. I wasted so much time on that part. This is not for the weak of heart, you really need to button down. Anton is one of the harder ones in the intro to Calculus, it spent more time in definitions and very straight from the begining. But it turn out that is very important as you get deeper into it. Easier books tend to be more relax in definitions and equations and try to explain in English. It does not work.

Look around for a beat up copy of Anton. Get the solution manual, it is very important as you need to work through the problems.

Also This is a free download online:
http://tutorial.math.lamar.edu/Classes/CalcI/CalcI.aspx

Follow the link and download the whole Calculus I II and III. It turn out to be one of the best I've seen. It is actually quite easy...for Calculus! I learn Calculus mainly from these two sources even I have like 7 or 8 books just in this topic. Buy more used books, buy cheap. They are really cheap online as students can't get rid of it fast enough after the course! I paid average less than $30 each for a book that was over $100 new! From all my studies, I filled up two 7' book shelves! Books are gold, like Chinese saying, you'll find a gold house inside books! Every one have their our taste, just like we have our own taste with woman. Just get more used books and find one that suit you.I am glad you have the experience that you run into break walls when you get deeper in electronics. There is no way out. It's not as if you use Calculus in the EE job, but you can't get pass the learning stage without it. Why do you think after 30 years of successful career, in my old retired years, I spent 2 years studying Calculus, nothing by Calculus, ODE and PDE. It is that important. I got so much insight in EM theory just from understand Calculus ( My bad, I should never say I understand Calculus, you never understand enough! But you get my point!). It is a language.

 

[eddie90]

I got a lot of Calculus book. Buy used one on Amazon particular the early editions really cheap. Not all books are equal. I am a self studier, I don't have an instructor to ask question. So I get a bunch of cheap used books to study, when ever I have a question I cannot understand from one book, I always manage to find better answer from another book.

I found the best book I ever studied in this subject is Calculus by Howard Anton, Irl Bivens and Stephen Davis. I tried to look for the 7th or the 8th edition used for you on Amazon and I can't find it now. It was dirt cheap a year or two ago. It is not easy, but again, just because the book looks easy don't mean it is good. I was fooled to choose the book by Sherman Stein because it looked easiest. But that was a disaster when I reach muli variable. It tried to be too simple that it starting to miss the point and confused. I wasted so much time on that part. This is not for the weak of heart, you really need to button down. Anton is one of the harder ones in the intro to Calculus, it spent more time in definitions and very straight from the begining. But it turn out that is very important as you get deeper into it. Easier books tend to be more relax in definitions and equations and try to explain in English. It does not work.

Look around for a beat up copy of Anton. Get the solution manual, it is very important as you need to work through the problems.

Also This is a free download online:
http://tutorial.math.lamar.edu/Classes/CalcI/CalcI.aspx

Follow the link and download the whole Calculus I II and III. It turn out to be one of the best I've seen. It is actually quite easy...for Calculus! I learn Calculus mainly from these two sources even I have like 7 or 8 books just in this topic. Buy more used books, buy cheap. They are really cheap online as students can't get rid of it fast enough after the course! I paid average less than $30 each for a book that was over $100 new! From all my studies, I filled up two 7' book shelves! Books are gold, like Chinese saying, you'll find a gold house inside books! Every one have their our taste, just like we have our own taste with woman. Just get more used books and find one that suit you.


I am glad you have the experience that you run into break walls when you get deeper in electronics. There is no way out. It's not as if you use Calculus in the EE job, but you can't get pass the learning stage without it. Why do you think after 30 years of successful career, in my old retired years, I spent 2 years studying Calculus, nothing by Calculus, ODE and PDE. It is that important. I got so much insight in EM theory just from understand Calculus ( My bad, I should never say I understand Calculus, you never understand enough! But you get my point!). It is a language.

Thanks a lot, I truly appreciate all the info you gave me. I will look into the books and the online recourse you mentioned. I learn better in my own than in a class some times so this should help me start getting ready for what's coming.

P.S. I tracked my shipment and it says it arrived at California on Saturday so I should be receiving it very soon

 

[yungman]

Thanks a lot, I truly appreciate all the info you gave me. I will look into the books and the online recourse you mentioned. I learn better in my own than in a class some times so this should help me start getting ready for what's coming.

P.S. I tracked my shipment and it says it arrived at California on Saturday so I should be receiving it very soon

I don't like to go to school either, I don't like the idea I am older than the professor!

Saturday?! Did you say you order from Digikey? That is slow, I always get my stuff from Digikey in 3 days! Find another place next time! I am in Calif, never wait for 4 or 5 days.

Are you living in the Bay Area? I am in San Jose area, they have Jamco in Belmont and I have Halt tech on Lawrence close to where I live. You can buy stuffs there walk in.

 

[eddie90]

I don't like to go to school either, I don't like the idea I am older than the professor!

Saturday?! Did you say you order from Digikey? That is slow, I always get my stuff from Digikey in 3 days! Find another place next time! I am in Calif, never wait for 4 or 5 days.

Are you living in the Bay Area? I am in San Jose area, they have Jamco in Belmont and I have Halt tech on Lawrence close to where I live. You can buy stuffs there walk in.

Lol yea it must not feel right. I just absorb material much better if I read it on my own. I've been told by a counselor that I have ADHD symptoms, I don't know if this has anything to do with it haha

Oh and yea, I'm not sure if you misunderstood me but I said that it got here to Cali this past Sat. It makes sense because I ordered on Thurs evening so on Sat it got to Cali and earlier today it said they received it at my local post office :D

Oh and I live in LA. I wish I knew stores like the ones you mentioned where I can just walk in. I tried searching for both of those in my area but I did not find any.

What can I search for? What would a store like that be called? All I have is radio shack, and you know they basically turned into a cell phone store now haha