Relay and timer - Electronic Circuits Projects Diagrams Free

TCDK · 12th April 2008, 02:46 PM

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 ?

KMoffett · 12th April 2008, 05:00 PM

http://www.electronics-lab.com/proje...014/index.html

The 555 will supply 200mA maximum current for the relay coil. If the relay coil requires more current you will need to add a reaistor and transistor to increase the drive.

Ken

TCDK · 15th April 2008, 08:38 AM

Uh thanks! looks very easy!

TCDK · 15th April 2008, 07:14 PM

One thing I dont get with this schematic.

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

KMoffett · 15th April 2008, 07:31 PM

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 · 15th April 2008, 07:33 PM

Quote:

Originally Posted by TCDK

One thing I dont get with this schematic.

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

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

TCDK · 15th April 2008, 10:28 PM

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

and the board:

EDIT: This is how I made the board now:

The sch file = layout_01.sch if anyone would like to play around with it.

TCDK · 16th April 2008, 10:19 AM

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 · 16th April 2008, 08:35 PM

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 · 21st April 2008, 05:11 PM

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 ?

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12th April 2008, 02:46 PM	(permalink)
TCDK	Relay and timer 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 ?

12th April 2008, 05:00 PM	(permalink)
KMoffett	http://www.electronics-lab.com/proje...014/index.html The 555 will supply 200mA maximum current for the relay coil. If the relay coil requires more current you will need to add a reaistor and transistor to increase the drive. Ken __________________ "To invent, you need a good imagination and a pile of junk." Thomas A. Edison (1847 - 1931)

15th April 2008, 08:38 AM	(permalink)
TCDK	Uh thanks! looks very easy!

15th April 2008, 07:14 PM	(permalink)
TCDK	One thing I dont get with this schematic. "pin 1" is GROUND on a 555, why should this be connected to 12v + ?

15th April 2008, 07:31 PM	(permalink)
KMoffett	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 __________________ "To invent, you need a good imagination and a pile of junk." Thomas A. Edison (1847 - 1931)

15th April 2008, 10:28 PM	(permalink)
TCDK	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 and the board: EDIT: This is how I made the board now: The sch file = layout_01.sch if anyone would like to play around with it. Last edited by TCDK; 16th April 2008 at 10:18 AM.

16th April 2008, 10:19 AM	(permalink)
TCDK	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.

16th April 2008, 08:35 PM	(permalink)
TCDK	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.

21st April 2008, 05:11 PM	(permalink)
TCDK	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 ?