I don't want it to work the all time

That could be a problem with the post #19 circuit as is. When PB1 (presumed to be a NC switch) is released after the timeout the D-flop will be left in an arbitrary state; so there's a 50% chance the load will stay energised. The CLR input of the D-flop could be fed from point PB via a diode, and grounded via a ~1meg resistor, to overcome this.

 

Apparently you didn't understand me. My circuit in post #10 will also do what you want. You have to hold the button down for several seconds to cause it to change state.

 

looking good - this is want I have wanted
Thanks !!

just 2 understanding questions:
1. the push button his job is to start the 555, right?
so isn't he need to be between the VCC and PIN8 ?
I don't want it to work the all time - its take to much mA,or am I wrong?
2. how did you calculate the 2.9 seconds? using witch R and C?


Thanks,

1. That will work also. See attached.

2. 1.1 x R x C
Where:
R = R2
C = C5

Also

I've attached 3 simulation graphs.

-1 shows PB pressed for 1 second
-2 shows PB pressed for 4 seconds
-3 shows PB pushed twice fro 4 seconds with a 4 second interval.

eT

 

That could be a problem with the post #19 circuit as is. When PB1 (presumed to be a NC switch) is released after the timeout the D-flop will be left in an arbitrary state; so there's a 50% chance the load will stay energised. The CLR input of the D-flop could be fed from point PB via a diode, and grounded via a ~1meg resistor, to overcome this.

hi Alec_T

See modified circuit (thread #23)

Does this address the issue you mentioned?

eT

 

Hi eeteach00,
it look very good - thanks
this is what I wanted!
press 3 sec for ON , press 3 sec again for OFF - simple !
I will start built it and if I have any problems I will ask again .

Thanks again!
just to be clear :
1. what do you mean by - "Bypass caps are not shown"?
were do I need to add them?
2. from I have read in the datasheet , the FDC638P can process up to 4.5A right? (some circuit I want to connect to it are using up to 1A)

Thanks ,

 

See modified circuit (thread #23). Does this address the issue you mentioned?

I'll play with a sim and let you know. Can you post the .asc file?

 

Hi eeteach00,
it look very good - thanks
this is what I wanted!
press 3 sec for ON , press 3 sec again for OFF - simple !
I will start built it and if I have any problems I will ask again .

Thanks again!
just to be clear :
1. what do you mean by - "Bypass caps are not shown"?
were do I need to add them?
2. from I have read in the datasheet , the FDC638P can process up to 4.5A right? (some circuit I want to connect to it are using up to 1A)

Thanks ,

1. I didn't show any "Bypass" capacitors, but it's a good practice is to connect a 0.1u or 0.01u capacitor at each IC +supply pin to ground. So 555 would need one at pin 8 and 4013 would need one at pin 14.

2. Yes, but I wouldn't operate it at 4.5A. Generally speaking, operate it at no more that half its max rating. So max operating current is about 2.25A. If your connecting a load of 1A should be OK but use with a decent heat sink.

eT

 

I understand .
it will take me a few day to built it ,
but I will let you know how it work

Thanks again !

 

it will take my a few more days until the part will arrive

just to be sure.....


Thanks .