Power-on Reset

[cardoso115]

Hello,

I have a problem, i have a circuit that is connected via a one shot with a flip flop.

But now I need a power on reset device so that the device won't turn on whenever i connect it to the power.

Thanks in advance for any help.

 

[sreid]

You could use a compairator with an RC at one input and 2.5V (resistive divider) at the other. Cap to ground, pullup to 5V, center of RC to compairator. Most FFs clear low so the RC goes to the compairator + input.

 

[felixc]

It depends how your monostable and flip-flop are used. Check if placing a RC circuit at the set or reset inputs of your flipflop makes sense.

 

[Chuckles159]

Maxim DS1233D. Holds its output low for 350mS on power up then goes high.