k0ma needs a 3V Delay timer schematic!!!

Heya all,

I know nothing of Electronics except in my secondary school projects.

What I need is a 3V timer schematic with a 0 ~ 10 second delay which then turns/operates a 3V relay.

Actualy this project is for my kids projects... i`m just sort of chippin in for him....
u can e-mail it to me at awiebc2004@yahoo.com or post it here or PM me by the name of k0ma.


THANX for the help ...u guys r great.!

this could do it
https://www.electronics-lab.com/projects/misc/014/index.html

Thank u pop. for the schematic but can this diagram be applicable using a 3V power source?.

Hi kOma,
That timer project uses an ordinary 555 IC like an LM555. It is spec'd for a minimum supply voltage of 5V, so it probably doesn't work with only 3V.
A Cmos version of the 555 like an LMC555 is guaranteed to work with a supply voltage as low as 1.5V, but can provide an output current of only a few mA at 3V and less.

The 3V model of the tiny extremely sensitive relay that I use needs 22mA.
So your 3V supply voltage requirement will cause many problems.
A solution would be to use the Cmos LMC555 driving a transistor to operate the relay. Maybe the transistor can replace the relay.
If your supply is an ordinary carbon-zinc or alkaline battery, its voltage will quickly fall to 2V. The Cmos with transistor circuit will work fine, but the 3V relay will stop functioning when the supply is less than about 2.5V.
If you are rich, a lithium battery will keep it going for a while.

How much current do you have to switch?