Question about general circuity

[Alex3k]

Out of curiosity do you all remember circuits? for example do you remember what value resistors to use with things like leds, picaxe chips and other components? or do you look things up? do you know what transistor to use at a certain point?

Ive been wondering this for a while now because i have to google everything, i know im new at this but still.

 

[inglewoodpete]

Out of curiosity do you all remember circuits? for example do you remember what value resistors to use with things like leds, picaxe chips and other components? or do you look things up? do you know what transistor to use at a certain point?

Ive been wondering this for a while now because i have to google everything, i know im new at this but still.

I started out like you. I learned circuit theory and the formulae required to design and understand circuits.

Some people remember football scores. Others remember circuit configurations and component values.

 

[Alex3k]

Do you have any recommendations on maybe websites or books that you used? more resources the better in my view.

 

[Dippy]

Yes, it was a jungle for me too.
If you learn the basics, as said by Pete, that gives a good starting point.

In many cases choosing a value is based on memory - it's called experience - and that can't all be learnt at school, though you can make a start right now.
Like learning the 'times tables' when you are 5 years old I don't have to think about how to work out 7x9.

I keep a notebook (and CAD folder) of more complicated things, sometimes jokingly called a 'grimoire' - look it up.

As you get more used to it you'll be able to design things based on the flow of currents - this is why the water/plumbing analogy can be useful.

But you really need to know the basics to get going.
And you need to understand what is going on to be able to do the calcs to define and refine your design.


It won't happen overnight. Effort in = Results out.
... and then you can design things without having to wait for a Forum answer .

Same with coding. After a few years the general code flow hovers in your mind's eye. Sad.


One thing I am certain of;
This question will provoke many replies .... you may have opened the Old Hack Reminiscing Floodgates.
"I remember in 1894 when Faraday showed me... .

Good luck.


PS. There a dozens of websites showing basic electronic function and design.
Spend an hour searching and then put ssome links here.
Otherwise you'll get a hundred replies with a 100 websites and you'll lose track.

 

[Alex3k]

Cheers for the insight, believe it or not it gives abit of peice of mind.

 

[SAborn]

I just found each project i done i learnt something new and other times finding a part of a circuit was the same as a previous one so you remembered that and the knowledge pool grew and grew and.............

As Dippy said its like learning math or a language etc, to start with its all learning but bit by bit you remember things and sooner or later you find you can string a circuit together, as you would a math problem or a sentence etc.

As they say Rome was not built in a day. ( but then they didnt have Picaxes either, well at least not the same ones we have here.)

 

[Radarman2]

I had a 2 or 3 year ONC course crammed into 9months that started off difficult, but the more you learnt of separate subjects (analogue, digital, electronic principles, radio, telecomms) the more you realised everything tied in and some basic knowledge would be applicable to all of the subjects.
Couple that with a healthy interest in learning, computing, design and making-things-bloody-well-work (also known as not giving up at the first hurdle) means that I can figure out a lot of this stuff, but with the occasional "Help" request.

Like Dippy said, find some good resource websites, there are also calculators out there (like calculate LED resistor value by entering values). Just don't rely on one source, people get things wrong, typos occur and plagiarism can copy the errors to other sites.

However, having said all of that I do still have a hard copy of all picaxe mauals as well as my diptrace printouts and code - computers are great, but I like to see multiple sheets still.

 

[geoff07]

Start off with Ohms Law V = I x R; I = V / R; R = V / I
If R is in K, I is in milliamps. Dead simple but it drives much of what we do, e.g for a 2v led running at 20 mA off a 5v output from a Picaxe:

R = V / I = (5-2) / 20 = 0.15 K = 150 ohms (minimum). Actually I usually use 1k or so as 20mA in a led is a lot.

As others have said, there are lots of electronics 1.01 courses on the internet, browse some of them. In fact the Picaxe book is pretty good if you can get a copy (Programming and Customizing the PICAXE Microcontroller 2nd Edition by David Lincoln) though it is a bit pricey. You need to know basic transistor configurations and why you use them, simple filters, decoupling, current limiting, etc.

Passive and Discrete Circuits (R M Marston, Newnes 2ed) is a very good reference with basic theory and reference circuits. I use mine all the time and I have a degree in Elec Eng. Amazon will find you a copy.

There are many was of doing things. But fewer than you might think going by the part numbers. For example, a BC148 is an NPN silicon transistor that will do most low power things you would need to do with a Picaxe, but it has thousands of similar but not always quite identical alternatives. But once you buy 50 BC148s (or whatever you choose) on ebay that tends to become the answer to most relevant problems. Most analogue circuits could be built with different components substituted, very rarely are you working at the limits of a component where the exact values are critical. Though you do need to understand what changes you are making.

Finally keep an A4 bound notebook, and write every design in it, including test results and ideas. That way you can build on your experience.

Good luck with the learning, it is an interesting hobby and can become the basis of a career (it did for me)

To prove Dippy right, I remember .. my first major project at 16 was a single conversion 455 IF superhet receiver with valves and a 300v DC HT supply. Probably illegal these days. But it worked, and I learned a lot. If you don't know what a superhet is, look it up.

 

[geezer88]

By far the best book for learning electronics in general that I have run across is "The Art of Electronics" by Paul Horowitz. The last edition was published in the late '80s, but the fundamentals haven't changed much.

tom

 

[Alex3k]

Cheers guys, i cant thank you enough!

 

[manuka]

My 2¢ worth from the colonies. Theory aside,confidence in any field (hunting, cooking, gardening, building, bee keeping, chatting with the ladies etc) comes from rolling-up-your-sleeves-and-getting-really-involved.

Experiencing the frustrations & agony of defeat means one may develop a "feel" for the craft, and hopefully know better next time. Spoil the cake with overcooking, shoot yourself in the foot while hunting,have your tomatoes go belly up, or get splinters in your hand/hit your thumb with the hammer & the memory will be keen. In electronics even the smell of cooked electrolytics, smouldering wiring, hot ICs or scorched resistors can give valuable insights! Yes- sometimes all of these in a single circuit. Old hands will verify this also applies (yeah-often especially applies!) to the ladies example above...

Having contacts with an expert will be extremely valuable as well- radio hams refer to these noble gents as "Elmers". Recently retired technical types are usually very friendly & open to assistance. They'll often donate you gear as well-perhaps offer to mow their lawn in return. Does anyone fit this specification in your region? Where exactly in "England" are you ?

You don't say your age or resources either, but -for starters- have you a multimeter ? Have you used it to measure currents & voltages in simple working circuits? I started when most circuits high voltage valve/tube & a dead simple VOM multimeter cost a weeks wages-you've now low voltage e-waste galore AND the web! Hence how about downloading such classic simulators as the esteemed "Crocodile Clips" (now handled by Yenka) ? Favourite texts aside, Forrest M. Mims III diverse hand drawn "Engineers mini notebooks" are near priceless aids I've found too.

Stan. (Electron wrangler since a 4 yo. rural pre-schooler.)

 

[flyingnunrt]

This is old but still relevant
"practical Solid-State Circuit Design" by Jerome E Olesky
published by
Howard W Sams & Co
Very Practical.
Covers heaps of stuff that you will use whislt playing with picaxes

 

[Jaguarjoe]

Marston has about a dozen books on various facets of electronics. The book mentioned above can be purchased from Amazon used for about $5. Its an older addition but its good just the same.
eBay has the ART of Electronics text book international edition for about $35. The workbook is about $25.
Malvino has/had a good textbook too, I don't recall the name of it though.

Documenting what you build is very important. You will find that most cook book circuits won't exactly fill your needs and you modify them. Note well what you did so that if you have to or want to go back to that circuit you'll know what you did. Nothing is more time consuming than trying to find a particular component you used in a prior design when you need it for a new design and you don't have part # or even a vendor name.

Becoming familiar with Spice programs like the totally free LTSpice IV from Linear Technology will allow you to imagineer to your hearts content without spending any money or blowing things up that you already spent good money for.