Time Delay Relay

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A time delay relay is a relay that stays on for a certain amount of time once activated. This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay. The time is adjustable from 0 to about 20 seconds with the parts specified. The current capacity of the circuit is only limited by what kind of relay you decide to use.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
R1	1	1 Meg Pot
R2	1	10 K 1/4 Watt Resistor
C1	1	10uf 25V Electrolytic Capacitor
C2	1	0.01uf Ceramic Disc Capacitor
D1,D2	2	1N914 Diodes
U1	1	555 Timer IC
RELAY	1	9V Relay
S1	1	1A 120V SPST Switch
MISC	1	Board, Wire, Socket For U1

Notes

R1 adjusts the on time.

You can use a different capacitor for C1 to change the maximum on time.

S1 is used to activate the timing cycle. S1 can be replaced by a NPN transistor so that the circuit may be triggered by a computer, other circuit, etc.

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Comments

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ruel i want to supply it 24v and my relay is 24v but i wont operate Saturday, December 29, 2012 10:56:41 PM

i already get the cicuit in 12 volt,but my problem is i would like to increase my voltage into 24v so also increases my relay into 224v but wont work or oerate,pls help what to add components or change?i want 24v dc to run my motor

Billy Time Delay Relay Thursday, December 13, 2012 1:29:45 AM

If I use 9V as my input power supply,,,, do I have to change anything else??? And,,, I am not going out to a relay,,, I am going directly to an E-Match,,, to trigger an ejection charge in a model rocket.... But I do want all the power I can get,,, to make sure the charge ignites.. Thanks...

mok Time Delay Relay Sunday, April 29, 2012 11:48:40 PM

I'm looking to adjust the time of the delay for 1week. How do I calculate the change required to the capacitor? i want to know more about delay...

Indrajit Biswas Time Delay Relay Tuesday, February 28, 2012 9:21:09 AM

Thanks for the circuit diagram. Last some days I was searching the same, which I want to used. I hope it will help to me.

Chris Stewart Time Delay Relay Saturday, January 21, 2012 6:37:01 PM

Aaron, I have know you through the RX-7 world for years. But when I go to search for a time delay relay to build one, your site comes up second on Google. Mind blowing. Water level low>water valve opened (heating system)

landon Time Delay Relay Wednesday, January 11, 2012 10:27:41 AM

I think this is exactly what I've been looking for! Thank you! Will this also work with a 12V relay, or is it limited to 9V? What would have to change to get it to work with a 12V relay?

gading Time Delay Relay Friday, September 16, 2011 4:47:36 AM

Hai this is a good delay that ever I see, but If I want to change Switch S1 with Light sensor switch, how this two circuit connected

Dave H Time Delay Relay Sunday, August 07, 2011 7:11:37 PM

i built this and get ~ 8 secs delay, I will try larger C1 for longer BUT there is a current drain when switch is off which will flatten the small battery in my circuit I need zero current drain when off! How can I achieve this please.

anonymous Time Delay Relay Tuesday, July 19, 2011 3:19:26 PM

hi can the relay be replaced with a transistor of some sort ad if so how would it be used to trigger a camera flash thanks

tala Time Delay Relay Friday, January 21, 2011 12:58:36 AM

hi can i use this to delay an output of another circuit?is so where can i connect the output of my circuit to the input of this circuit? TY

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ruel	i want to supply it 24v and my relay is 24v but i wont operate	Saturday, December 29, 2012 10:56:41 PM
i already get the cicuit in 12 volt,but my problem is i would like to increase my voltage into 24v so also increases my relay into 224v but wont work or oerate,pls help what to add components or change?i want 24v dc to run my motor
Billy	Time Delay Relay	Thursday, December 13, 2012 1:29:45 AM
If I use 9V as my input power supply,,,, do I have to change anything else??? And,,, I am not going out to a relay,,, I am going directly to an E-Match,,, to trigger an ejection charge in a model rocket.... But I do want all the power I can get,,, to make sure the charge ignites.. Thanks...
mok	Time Delay Relay	Sunday, April 29, 2012 11:48:40 PM
I'm looking to adjust the time of the delay for 1week. How do I calculate the change required to the capacitor? i want to know more about delay...
Indrajit Biswas	Time Delay Relay	Tuesday, February 28, 2012 9:21:09 AM
Thanks for the circuit diagram. Last some days I was searching the same, which I want to used. I hope it will help to me.
Chris Stewart	Time Delay Relay	Saturday, January 21, 2012 6:37:01 PM
Aaron, I have know you through the RX-7 world for years. But when I go to search for a time delay relay to build one, your site comes up second on Google. Mind blowing. Water level low>water valve opened (heating system)
landon	Time Delay Relay	Wednesday, January 11, 2012 10:27:41 AM
I think this is exactly what I've been looking for! Thank you! Will this also work with a 12V relay, or is it limited to 9V? What would have to change to get it to work with a 12V relay?
gading	Time Delay Relay	Friday, September 16, 2011 4:47:36 AM
Hai this is a good delay that ever I see, but If I want to change Switch S1 with Light sensor switch, how this two circuit connected
Dave H	Time Delay Relay	Sunday, August 07, 2011 7:11:37 PM
i built this and get ~ 8 secs delay, I will try larger C1 for longer BUT there is a current drain when switch is off which will flatten the small battery in my circuit I need zero current drain when off! How can I achieve this please.
anonymous	Time Delay Relay	Tuesday, July 19, 2011 3:19:26 PM
hi can the relay be replaced with a transistor of some sort ad if so how would it be used to trigger a camera flash thanks
tala	Time Delay Relay	Friday, January 21, 2011 12:58:36 AM
hi can i use this to delay an output of another circuit?is so where can i connect the output of my circuit to the input of this circuit? TY