Electronics How's a Not gate work?

I was reading my physics text book (not really any good starting now after I've finished exams) and I read through the section on logic gates. Anyway here are two circuits. In the first one the bulb shouldn't light. In the third one according to logic it should. But it blatently won't. How does a Not gate output a signal when it receives no signal? Same thing goes for Nand and Nor gates I guess.

 

The thing that the schem doesn't show (as it's more or less implied) are the Vcc and Vdd for the NOT gate, which is where the output gets its power from.

 

im gonna assume u meant second

a not gate has a power supply too but u dont show it on the diagram which means the second circuit might work (but might not i think cmos chips would fry them selves)

to make it simple

logic 1 = 5v
lovic 0 = 0v

if input is 1 output is 0
if input is 0 output is 1

and you dont draw the power supply pins in a circuit diag

 

What the hell is the Vcc and Vdd? My physics book didn't mention that. Oh and what does a logic gate actually look like as a component?

 

it looks like a 14 pin IC

2 of the pins are used for power and ground (called vcc and vdd not sure which is which tho) and the other 12 pins are used for not gates so it will have 6 not gates in one chip

 

Ah I see. They could have explained that rather than assuming we'd know there was a hidden power supply anyway thanks guys.

 

Vcc = Voltage for Common Collector (Positive)
Vdd = Venereal....wait, we're talking electronics still
Vdd = AcronymFinder says its "Votlage drain drain", which I don't think is quite right. Anyway, it just means negative.

 

A not gate is just an inverter.

You were right about the input of 1 giving an output of 0.

 

yea a not gate is an inverter changes 1 to 0 and 0 to 1

 

If I had my computer working I could show you the diagrams for both CMOS and TTL (normal) Not gates but both work on the consept of a potential divider. Basically you put the transistor as the lower resistor and when it is turned on the resistor at the top "gobbles" up all the voltage and so the output is 0 but when the transistor is off the resistor doesnt and so the output is 1. I realy need to have a diagram to explain it but that is baisally it CMOS is a bit different but you dont need to know that.

I am doing work experience at ARM doing very strange stuff with bellow trasistor level stuff which is how i came accross some of this stuff. Realy realy interesting area however I have had to sign an NDA