bit-tech.net

Electronics Guide Part 1 - the Basics

Comments 1 to 25 of 33

Reply
<A88> 29th April 2005, 08:54 Quote
Brilliant ;) Been looking for an electronics guide to suite my n00biness and this fits perfectly. Bring on Pt2!

<A88>
g0th 29th April 2005, 09:09 Quote
Great stuff.

I would like to make a couple of suggestions.

When calculating resistors for LED use, remember to work out the power dissipation in the resistor and choose a resistor that can handle it.

This is almost never a problem for 1 or 2 LED's, but put a heap of LED's in parallel and you can start burning resistors.

Because LED's are a PN junction device, the potential across them is fixed, provided the supply voltage is at least the forward voltage. This is what makes it possible to choose a resistor to limit the current from a suitable value.

Feel free to take or paraphrase material from here,

http://forums.bit-tech.net/showthread.php?t=88511

But if you do this i would like to be credited in the article.

I'd be happy to make suggestions / comments / help write future parts.
RotoSequence 29th April 2005, 17:20 Quote
Great to see an electronics guide on bit-tech at long last ;) Good job, Acrimonious; I look forward to reading part two :D
Zidane 29th April 2005, 17:23 Quote
cool first part, makes a lot of sense. hopefully this will stop me posting "help, im a n00b!" posts int he electronics forum... ;)

eagerly looking forward to the full series, and creating some cool stuff to make my cases a little more whizz-bang
Nath 29th April 2005, 18:04 Quote
Looks very useful, will stay tuned for part 2! :D
Hippo 29th April 2005, 18:16 Quote
Good beginners guide, I cant wait for the section on Thevenin and Nortons theorems :D
Fatboy 29th April 2005, 20:09 Quote
WooooO00o0o0o0o0o0 yay.

A modding article for a change ;)

Very well written, if i 'twas a noob id understand that well!

Certainly easier than Q= 1/2CV^2 or other pants like that.
mannafig 29th April 2005, 20:22 Quote
at last a beginners guide that i can understand.looking forward to part 2 ;)
Alwayz Dead 29th April 2005, 21:05 Quote
Great stuff
I'm not the most prolific poster but I use BitTech as a source of reference a great deal and this addtion makes it only more useful.

Nice one ;)
g0th 30th April 2005, 03:55 Quote
Quote:
Originally Posted by Hippo
Good beginners guide, I cant wait for the section on Thevenin and Nortons theorems :D

You wouldn't really use them in basic practical modding electronics
Etacovda 30th April 2005, 05:37 Quote
rough guess here (a guess, mind you)

hes being sarcastic/joking...
Sc0rian 30th April 2005, 08:52 Quote
sweet.

Nice one acrim.

- S
Hippo 30th April 2005, 09:19 Quote
Off Topic: Interesting how the New Zealander understood the sarcasm and the aussie didnt. Read into it what you will :)
gmail 30th April 2005, 13:37 Quote
ye, thats a really good guide for noobss like me :D :D
nleahcim 3rd May 2005, 00:59 Quote
Last time I checked, current was a flow of positive charge, not of electrons.
g0th 3rd May 2005, 05:16 Quote
In the majority of cases, current flowing through solid metals, or graphite, etc, the sole charge carriers are electrons.
nleahcim 3rd May 2005, 07:36 Quote
Quote:
Originally Posted by g0th
In the majority of cases, current flowing through solid metals, or graphite, etc, the sole charge carriers are electrons.
Correct.

That still doesn't change the fact that current is the measure of postive charge flow.
g0th 3rd May 2005, 08:52 Quote
Yeah, you're talking about 'conventional current', which is one of the Stupidest Things Ever.
acrimonious 3rd May 2005, 10:32 Quote
Quote:
Originally Posted by nleahcim
Correct.

That still doesn't change the fact that current is the measure of postive charge flow.

Thanks for taking an interest.

I see where you're coming from - but positive charge arises due to electrons flowing in the opposite direction. The more electrons flow, the greater the 'positive charge flow' and so the greater the current.

In some respects I am wrong to say that electricity comes about due to electrons as electricity can arise due to proton flow in liquid metals - however I'm just going to be working with Molexs, not mecury, so for the first part of the guide at least, I think this level of understanding is far more than enough. ;)
nleahcim 3rd May 2005, 18:59 Quote
Quote:
Originally Posted by g0th
Yeah, you're talking about 'conventional current', which is one of the Stupidest Things Ever.
It may seem stupid, but it's also the standard convention.
Quote:
Originally Posted by acrimonious
Thanks for taking an interest.

I see where you're coming from - but positive charge arises due to electrons flowing in the opposite direction. The more electrons flow, the greater the 'positive charge flow' and so the greater the current.

In some respects I am wrong to say that electricity comes about due to electrons as electricity can arise due to proton flow in liquid metals - however I'm just going to be working with Molexs, not mecury, so for the first part of the guide at least, I think this level of understanding is far more than enough. ;)
I don't agree. People should learn the right thing first, not be taught a half right thing and then later be expected to figure out what is actually going on. You're just going to get people confused if you tell them something that is blatantly wrong.
acrimonious 3rd May 2005, 19:40 Quote
Quote:
Originally Posted by nleahcim
It may seem stupid, but it's also the standard convention.

I don't agree. People should learn the right thing first, not be taught a half right thing and then later be expected to figure out what is actually going on. You're just going to get people confused if you tell them something that is blatantly wrong.

I honestly think that calling a two page article about the basics of electricity "blatantly wrong" for not highlighting the phenomenon of proton or atom currents is being every so slightly pedantic.

If someone gets confused in the course of following these basic electromodding articles due to this omission I'll paypal you a beer. ;)
Fatboy 3rd May 2005, 20:17 Quote
Quote:
Originally Posted by acrimonious
I honestly think that calling a two page article about the basics of electricity "blatantly wrong" for not highlighting the phenomenon of proton or atom currents is being every so slightly pedantic.

If someone gets confused in the course of following these basic electromodding articles due to this omission I'll paypal you a beer. ;)


Owned.

Its like being in the first year at school in chemistry. you learn a basic idea that works until you can reach a higher level (like a levels), where you learn it a different way which is more correct but difficukt to understand.
nleahcim 4th May 2005, 00:58 Quote
Quote:
Originally Posted by acrimonious
I honestly think that calling a two page article about the basics of electricity "blatantly wrong" for not highlighting the phenomenon of proton or atom currents is being every so slightly pedantic.

If someone gets confused in the course of following these basic electromodding articles due to this omission I'll paypal you a beer. ;)
Why not just say positive charge, instead of electrons? Then the guide would be right, and newbs would actually have the right idea, somewhat. The problem is if they look at another tutorial - there's a very good chance they'll get confused as it probabaly will reference the flow of positive charge. I'm actually quite surprised that you are arguing against me on this... You're just going to confuse newbs worse if you tell them something that is wrong, IMHO.

I'll be expecting that beer soon. Blue moon would be good, but a Guinness is acceptable as well :D
acrimonious 4th May 2005, 14:34 Quote
Quote:
Originally Posted by nleahcim
Why not just say positive charge, instead of electrons? Then the guide would be right, and newbs would actually have the right idea, somewhat. The problem is if they look at another tutorial - there's a very good chance they'll get confused as it probabaly will reference the flow of positive charge. I'm actually quite surprised that you are arguing against me on this... You're just going to confuse newbs worse if you tell them something that is wrong, IMHO.

I'll be expecting that beer soon. Blue moon would be good, but a Guinness is acceptable as well :D

Because, due to past experience of teaching and writing about electronics, I feel that people grasp the concept better if you explain it in terms of something tangable that they already have an idea of - like electrons - rather than a more imaginary quantity that arises due to them.

I completely disagree that I am wrong not to include "positive" charge in my definition of current. So much so that you've gone and made me get my dictionary of electronics out - shesh. It has this to say on the subject:
Quote:
current Symbol: I; unit: ampere. A flow of electric charge or, quantitatively, the rate of flow of electric charge. A conduction current is a current flowing in a conductor due to the movement of electrons or ions through the material, usually under the influence of an applied field. The net current is the algebraic sum of the charges. >>displacement current.
A unidirectional current is one that always flows in the same direction in a circuit. A unidirectional current of more or less constant magnitude is a >direct current. >>alternating current.

Furthermore, The Art Of Electronics by Horowitz and Hill 2nd Edition - generally considered to be the bible of electronics - says on current:
Quote:
Current (symbol: I). Current is the rate of flow of electric charge past a point. The unit of measure is the ampere, or amp, with currents usually expressed in amperes (A), ...
g0th 4th May 2005, 17:08 Quote
Right, current is dQ/dt.

The type of charge carriers is irrelevant.

Conventional current, such as when it is drawn in on a schematic, is the direction positive charge carriers would flow, if they were able to flow.

I say briefly mention this idea, and mention that in a circuit with solid conductors, it's really electrons that flow, in the oppisite direction (electron current), but leave it at that. That's more than adequate for our purposes.
Log in

You are not logged in, please login with your forum account below. If you don't already have an account please register to start contributing.



Discuss in the forums