h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

How do you _make_ an AND gate? Is what I asked, the truth tables tell you what it _is_ also, how are the inputs and outputs aranged on the half adder, I expect you to know these things you've got an MSc for bob's sake. Also what grade do you get if you make a binary adding machine for technology at school?

How do I make an And gate? Maybe I'm not getting the question, or maybe I'm just tired today, but that makes no sense to me.

A AND B gives the carry
A XOR B gives the sum

I refuse to answer any more questions. The point of this was to prove logic. Also to annoy EC.

You make an AND gate by taking an OR gate ant placing a NOT gate before each of the inputs and a further NOT gate after the output so I'm more logical than you

Meh. There are other ways to create an And gate. But that'll just be getting silly so I won't go into them (i once spent way too much of time figuring out different ways of creating specific gates in as many convoluted ways as possible. Time well spent...)

Yes, nut if you are, oh I don't know, maybe making a binary adding machine from scratch using bits you can buy in Maplins/Radio Shack then that's how you make your and gates

that should be 'Yes, but...'

Yes but...why would anyone do that?

Binary adding machines are cool...but
You dont by any chance have a binary watch do you?

Well, I AM annoyed.

Look missus, I was 15 and fedup with making stupid display cabinets and plastic thingies and boardgames and stuff.

I'm confused. And still annoyed.

When I was at school I built a, very basic, calculator from bits and pieces because it was more fun than the dull crap we normally made in technology

Its people like you that fill me with amazement. And possibly also people like you what cause unrest.

oh all it could o was add any two numbers between 0 and 31 but it was fun to make, the hardest part was making the logic gates from scratch...oh and it was the size of a 21"TV

Man, why couldn't you be vaguely referential and make an calculator that couldn't do any sums that equalled higher than four or something. And then the calcular would say something about the color yellow instead of giving an error message...

hmm thats quite interesting actually. How did you end up making the logic gates then from scratch?

And why is EC confused?

well OR gates were easy, it just consisted of a implr Y shaped circuit on a PCB with diodes to keep the electricity flowing in one direction. Not gates I made using an electromagnet and a sort of inverted reed switch I bodged together. That is I had a switch where the switch it's self is on a spring and normally closed (NC) when a current is aplied to the input it activates the magnet pulling the NC switch open. I then used these to make my AND gates and XOR gates.

Impressive. So what subject did you attempt to study at uni then?

ICT, Expressive English and Art. Also I have done bits of maths, prysics, chemistry, history, geography and nursing

Ahhhhh. Wow. Quite a variety there! I'm surprised that you didn't do a degree straight in soemthing like electronic engineering or something as I would've thought that's the kind of thing that would've fascinated you!

I can't do degrees. I'm ok for about 1'5 yrs, then I start to fall behind. I could probably just cope with 2yrs, but by the time I get to three I'm too far behind to catch up.