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EDIT: DM7474 specification.
EDIT-2: Circuit with CD4013 added

or

 

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View attachment 170397

Thanks, Danko, that is indeed what I was talking about. I have not used a 7474 so I was reluctant to give advice on it.

 

I am gona buy cd4013 becose 7474 can only uostand an input voltage maximum 7 vdc and my input is 12 so it will fry it and cd4013 i think it can use 15vdc and thats perfec for my aplication beacose i need to power 12v relay ofcorse i will put transistor beacose the chip can't power the relay and for the rest pin i will need the circuit when i powerit to stay off and when senses pulse of 5 vdc than to turn on

 

Reset pin sorry not rest

 

And thanks for all the replays it has helped me alot

 

I am gona buy cd4013 becose 7474 can only uostand an input voltage maximum 7 vdc and my input is 12 so it will fry it and cd4013 i think it can use 15vdc and thats perfec for my aplication beacose i need to power 12v relay ofcorse i will put transistor beacose the chip can't power the relay and for the rest pin i will need the circuit when i powerit to stay off and when senses pulse of 5 vdc than to turn on

To drive a relay, if you know the coil current, check the sink capability of the CD 4049 hex inverter when it is running on 12 or 13 volts. All six in parallel might be enough.
ALSO, be sure to avoid excess V to those CMOS devices. The published limits are true!

 

There are a lot of circuits that run on 12 volts. What concerns me is when people think of a car electrical system. Though it's a 12 volt system it can see voltages as high as 14.4 volts after engine startup. What's more, car electronics are notoriously noisy. I learned that a long time ago when I built a 12 volt circuit for my car. It lasted about 2 weeks before it was dead. Back then I understood very little about electronics and what I was learning I got from magazines. They helped a lot, but there was a lot not discussed. So if this is a circuit you're building for a car - beware of transient spikes that can fry your CMOS circuitry.

 

Nope i am not building it for car system

 

I

To drive a relay, if you know the coil current, check the sink capability of the CD 4049 hex inverter when it is running on 12 or 13 volts. All six in parallel might be enough.
ALSO, be sure to avoid excess V to those CMOS devices. The published limits are true!

Its easyer to put transistor andnot make the circuit more complicated beacose i need space for the pcb that i am gona build it

 

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View attachment 170403
EDIT: DM7474 specification.
EDIT-2: Circuit with CD4013 added
View attachment 170467
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View attachment 170471

Yes thats exactly what i wanted to do with the mosfet and diode parallel on the relay for voltage spikes

 

Yes thats exactly what i wanted to do with the mosfet and diode parallel on the relay for voltage spikes

OK, and if the relay takes more than about 50mA that is the way to go. BUT using one IC with no extra components is NOT more complicated than using an FET or MOSFET or even a bipolar transistor.

 

OK, and if the relay takes more than about 50mA that is the way to go. BUT using one IC with no extra components is NOT more complicated than using an FET or MOSFET or even a bipolar transistor.

I am using a big car relay it draws 800ma its an 80A relay it's realy big

 

I am using a big car relay it draws 800ma its an 80A relay it's realy big

In that case my suggestion will not work. That is why I added the qualifiers about the relay current. With a relay like that you do need to include protection against inductive spike voltages, but at the same time you need to avoid slowing down the contacts opening to preserve contact life.

 

In that case my suggestion will not work. That is why I added the qualifiers about the relay current. With a relay like that you do need to include protection against inductive spike voltages, but at the same time you need to avoid slowing down the contacts opening to preserve contact life.

I think the parallel diode is enough for voltage spikes and i will put another diode series to the coil and that should be good