flip flop switch to control mosfet

[mika]

Hi im traing to do one flip flop, and i view the video from eevblog, https://www.youtube.com/watch?v=Foc9R0dC2iI&feature=youtu.be, the circuit that im interesting appears in minute 13:03.
The caracteristics how i need are   not auto-turn on when conect the power and the delay to turn off.
if i understand this delay is produced for the low voltage 3v?
circuit i see

its posible to controle with this circuit a mosfet like a switch ? i tell a mosfet because i need the memory from the mosfet  only 5,7 seconds in case that the power disconected after the mosfet would have to restart. 

thanks for all.

[Paul Price]

No.
This circuit will not give you a delay in turning off the power.

The circuit you show will instantly begin to turn off power by holding pressed the on/off momentary contact switch if the  P-channel MOSFET switch has already been turned on power by a previous switch press.

You might do much better to get  the accurate turn-off delay that you want using a CMOS 4013 Dual D Flip-Flop. You would only need one of the two flip flops.

You would still use capacitors and resistors to create charging delays on the Set pin and Clock pin and you could also use the D input pin to make your Power On/OFF switch.

The NOT Q output of the 4013 flip-fop would still connect to a P-Channel MOSFET acting as the Power Switch to turn On/Off power.
You could do all this using just one switch to toggle on/off, just like as with the circuit you show.

The NOT Q or Q output of the 4013 flip-flop can be connected to the gate of a P-Channel power switch to control Power On or Off.

[mika]

Sorry paul,

 i explain bad, i not need a delay, i need, the effect holding pressed the on/off button to turn off.

The time of holding pressed 5-7 seconds.

How i can regulate the  time holding  pressed button?  changing the capacitor? 

i do that athis schematic with  4130, but i havent got , the effect to holding pressed button to turn off only

in that diagram if i chgange the relay for a p mosfet, if i disconected the power supply,
how i can reset  the memory of the mosfet  with  5-7  after disconected? 


thnaks for your help.