URGENT. Help on Power of Inverter.

> i would like to knw what is the condition required for power to consume.
First try this:
Switch both of the fets half way on...
So instead of applying a '1' or a '0', choose a '1/2' (with 5V supply 
this is about 2.5V). A little hint here: have a look for the threshold 
voltage of the fets.

And then step two:
What happens, when you switch from 0 to 1 and back very very fast?
Each time you have to cross the 2.5V.
And additionally: you have to charge and dirscharge parasitic capacitors 
at the output (not drawn in the picture...)
Both effetcs consume power.

erm. im just learning theory. im only required to find out the 
condition, is it this ---> significant power is only drawn whn the 
transistors in the CMOS device are switching between on and of states?

Yes.

Lothar Miller wrote:
> Yes.

okay. great, thanks. :)

Lothar Miller wrote:
> Yes.

on and off meaning switching from 1 to 0 right?

> on and off meaning switching from 1 to 0 right?
Hmmm... You got something wrong... :-/
To keep it short: excessive power is consumed if you don't apply to the 
input a steady 1 or a solid 0, but "something in between". This I meant 
with the phrase "1/2"...

And this "something in between" you can achieve by simply leaving the 
input unconnected. Then both of the gate will charge up to a 
intermediate voltage, and both of the transistors will conduct corrent 
from Vcc to GND. This case is widely known as a short circuit.

Lothar Miller wrote:
>> on and off meaning switching from 1 to 0 right?
> Hmmm... You got something wrong... :-/
> To keep it short: excessive power is consumed if you don't apply to the
> input a steady 1 or a solid 0, but "something in between". This I meant
> with the phrase "1/2"...
>
> And this "something in between" you can achieve by simply leaving the
> input unconnected. Then both of the gate will charge up to a
> intermediate voltage, and both of the transistors will conduct corrent
> from Vcc to GND. This case is widely known as a short circuit.

okay! got it. thanks so much! :)

Lothar Miller wrote:
>> on and off meaning switching from 1 to 0 right?
> Hmmm... You got something wrong... :-/
> To keep it short: excessive power is consumed if you don't apply to the
> input a steady 1 or a solid 0, but "something in between". This I meant
> with the phrase "1/2"...
>
> And this "something in between" you can achieve by simply leaving the
> input unconnected. Then both of the gate will charge up to a
> intermediate voltage, and both of the transistors will conduct corrent
> from Vcc to GND. This case is widely known as a short circuit.

actually what do you mean by 'simply leaving the input *unconnected*'

> actually what do you mean by 'simply leaving the input *unconnected*'
- leave it floating
- do not connect a external signal to it
- do not apply GND or Vcc/5V to it

Lothar Miller wrote:
>> actually what do you mean by 'simply leaving the input *unconnected*'
> - leave it /floating/
> - do not connect a external signal to it
> - do not apply GND or Vcc/5V to it

okay! thanks again!