relay

[brianmay27]

i think this is the place to put it. i am looking in a dc (15v) relay. i want to have it so i press a butten and it opens for 5 or so seconts. i cant find how to do this so does any one know how i may go about doing this. thanks

[Externet]

Hi. An electronics forum would more apropiate, but I can help.

If you have experience with integrated circuits, you could build a timer circuit using a very common 555 chip, its related components, switch and relay.

 

If you are not familiar handling circuits, buy a timer relay from an industrial electric store, or salvage a wiper timer relay from a wreck yard.

 

Miguel

[YT2095]

a simple RC and transistor will do it, you press a switch that fully charges the Cap and that charge supplies the base current to hold the transistor on. the resistor goes across the capacitor to discharge it over time (5 seconds in your case). the transistor supplies the power for the relays coil.

 

Simple eh

[najib]

a simple RC and transistor will do it,

 

 

I call this an RC memory

[Rocket Man]

how accurate does your five seconds need to be?

i built the circuit yt suggested a while back with a trimpot as a time delay for a speaker, the pcb would have fit snugly between the pins of a relay.

if you need a really accurate 5s, you'd probably be best off with the 555.

[weknowthewor]

just press the switch, then have a timer circuit(ic 555 timer), put to 5 seconds or whatever needed you will find ur ckt working as per ur wish