Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Relay and timer

Status
Not open for further replies.

TCDK

New Member
Hi

I've build a very simple circiut with a 12V / 220V relay.

When the relay gets an 12V signal, it triggers the 220V.


Now I want to add an timer to this relay, so when there is an 12V signal, an timer sends a variable signal (3-10s) to the relay.
So everytime the is a 12V signal, the relay will be triggered for some seconds.


Does anyone know how I could make this? and what parts to use ?
 

TCDK

New Member
One thing I dont get with this schematic.

"pin 1" is GROUND on a 555, why should this be connected to 12v + ?

**broken link removed**
 

KMoffett

Well-Known Member
Maybe I'm misunderstanding you, or you're misunderstanding "Ground". The "Ground" on the 555 (pin 1) goes to the negative side of the 12v supply. The little upside-down pine tree symbol at the bottom is "Ground", and the negative side of the 12v supply.

Ken
 

ericgibbs

Well-Known Member
Most Helpful Member
TCDK said:
One thing I dont get with this schematic.

"pin 1" is GROUND on a 555, why should this be connected to 12v + ?

**broken link removed**

hi,
Pin 1 is connected to ground/0V not +12V ....:confused:
 

TCDK

New Member
Ok, I draw it in Eagle, and now I understand :)

This is my first schematic drawings, so they are a little messy.


If anyone would like to put it better together it would be great.

See what im talking about :eek:

**broken link removed**

and the board:

EDIT: This is how I made the board now:

**broken link removed**

**broken link removed** if anyone would like to play around with it.
 
Last edited:

TCDK

New Member
I tryed to set it up on a hole island board.

First time I powered it up, with a wrong connection.

Is there anyway I can check if there are any parts that have been fried?


Does the above board seem ok? it dosen't show any faults when testing in Eagle.
 

TCDK

New Member
Got it to work now.

Only thing, if I turn up to trimmpotmeter over ~3sec, it dosen't release again.

Think maybe the trimm is broken - I will get another one soon.

Now it's only the print making left.
 

TCDK

New Member
Now I got this up and working, but would like to add an little extra feature.

The contact/switch will in my case be a floatswitch.
I would like to make something where I can ensure that if the floatswitch is somehow stuck, I wont keap sending and signal to the relay.

Aka. if the 555 timer gets an on (holding) signal that isen't released again the 555 wil cut of the signal to the relay as it should.

Now it just tricks the relay and keep it on (if I hold the switch on forever)

So maybe the 555 should have an signal there is cut of between the switch and the 555, or can the 55 somehow be set to only trigger once ?
 
Status
Not open for further replies.
Top