Time Delay Relay II

Author	Views	Views Today	Rank	Comments
jawaharlal@excite.com	80,917	61		34

When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. 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
C1	1	See Notes
R1	1	See Notes
D1	1	1N914 Diode
U1	1	4011 CMOS NAND Gate IC
K1	1	6V Relay
S1	1	Normally Open Push Button Switch
MISC	1	Board, Wire, Socket For U1

Notes

Email jawaharlal@excite.com with comments, questions, etc.

To calculate the time delay, use the equation R1 * C1 * 0.85=T, where R1 is the value of R1 in Ohms, C1 is the value of C1 in uF, and T is the time delay in seconds.

S1 may be replaced with an NPN transistor so the circuit can be triggered by a computer, other circuits, etc.

Most any 6V relay will work for K1. If you use a large relay, you my need to add a transistor to the output of the circuit in order to drive the larger load.

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Comments

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anonymous Time Delay Relay II Monday, April 06, 2009 12:52:52 AM

Your Note # 2 above reads 2, To calculate the time delay, use the equation R1 * C1 * 0.85=T, where R1 is the value of R1 in Ohms, C1 is the value of C1 in uF, and T is the time delay in seconds. Shouldn't that read C1 in farads?

CK Ong Time Delay Relay II Monday, February 09, 2009 11:40:23 AM

Hi there, I'm a 3rd year student looking to build a simple variable delay circuit to delay continuous pulses to LEDs from an arbitary waveform generator. I'm wondering if this design is feasible for delays in the range of about 100 nanosecond to 10s of microsecond? Please advice, thanks. Best Regards, CK Ong

robin Time Delay Relay II Saturday, November 15, 2008 10:53:48 AM

Following your notes, I put R-1 = 50 ohm and C-1 = 10 microFarad to get timer on about 7 minutes after connecting toggle S-1 ( 50x10x0.85 = 425 seconds, equal to 7 minutes plus). With toggle S-1 still connected, I'm waiting my 6 volt relay on. But after 20 minutes there's nothing happened .... May I have your kind advice for such problem ... shall I check certain point in that circuit ? Thanks so much for your kind attention. Robin - Jakarta

Patick S kennedy Time Delay Relay II Friday, October 31, 2008 11:53:31 AM

I'm looking for a timmer or timing circuit for a start of day/break/lunch/end of day bell.What is needed is a timmer that will ring the bell at the start of a period and ring again at the end of the period.The bell system already exsists and the owner does not want to replace it. Thank You Patrick S Kennedy Natco Industries West Warwick RI

Craig Time Delay Relay II Monday, October 27, 2008 11:38:18 AM

I am building a component that needs to activate a 12vdc 2amp solenoid for 2 or 3 seconds after a trigger switch has sent a signal. The trigger switch is human activated and will not stay open for the full 2 or 3 seconds. Is there a simple circuit for this operation that you know of?

Mauricio Time Delay Relay II Wednesday, October 08, 2008 8:00:47 AM

Hi there. I want to make a paintball 'bomb' that after 10 min activates the relay, which is connected to an alarm siren, but also 1 min from the end (at 9min.) it activates another siren, a warning siren... I already have the sirens. I also wanted a beep sound every second so that the bomb can be traced. I don't mind having 3 different circuits but need help to make them... Been trying to but the 555 timer is on at the start but the 4011 might work... Thanks in advance

anonymous Time Delay Relay II Friday, September 19, 2008 9:46:18 AM

te first time you switch S1 on in works ....but te second time te circuit doesnt works as it should ...te capacitor beeing carhged from the first time ...there will be no delay on te second push of S1 ( excuse my english :D )

Steve Time Delay Relay Saturday, May 31, 2008 4:22:47 AM

With reference to the Time Delay Relay page, if activated (by S1), the circuit should keep the relay on for the fixed time, say 20 seconds. However, after it switches off at the end of the first 20 seconds, it is not clear whether the relay will switch on again, i.e. S1 continues to be active.

Genlock Time Delay Relay II Wednesday, May 21, 2008 10:16:25 AM

Can a 555 timer be used to delay the output for 1 second after the footswitch is actuated?If so how is it configured.

Genlock Time Delay Relay II Wednesday, May 21, 2008 10:13:38 AM

I need to trigger an X-ray tube 1 sec after an imager and disconnect when the switch is open.I'm using a footswitch.I figure 1 mega ohm and 1 microfarad cap should give me 1 second.It may need to trigger up to 120 volts ac by relay.Will your circuit do this for me and do you have any suggestions?

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anonymous	Time Delay Relay II	Monday, April 06, 2009 12:52:52 AM
Your Note # 2 above reads 2, To calculate the time delay, use the equation R1 * C1 * 0.85=T, where R1 is the value of R1 in Ohms, C1 is the value of C1 in uF, and T is the time delay in seconds. Shouldn't that read C1 in farads?
CK Ong	Time Delay Relay II	Monday, February 09, 2009 11:40:23 AM
Hi there, I'm a 3rd year student looking to build a simple variable delay circuit to delay continuous pulses to LEDs from an arbitary waveform generator. I'm wondering if this design is feasible for delays in the range of about 100 nanosecond to 10s of microsecond? Please advice, thanks. Best Regards, CK Ong
robin	Time Delay Relay II	Saturday, November 15, 2008 10:53:48 AM
Following your notes, I put R-1 = 50 ohm and C-1 = 10 microFarad to get timer on about 7 minutes after connecting toggle S-1 ( 50x10x0.85 = 425 seconds, equal to 7 minutes plus). With toggle S-1 still connected, I'm waiting my 6 volt relay on. But after 20 minutes there's nothing happened .... May I have your kind advice for such problem ... shall I check certain point in that circuit ? Thanks so much for your kind attention. Robin - Jakarta
Patick S kennedy	Time Delay Relay II	Friday, October 31, 2008 11:53:31 AM
I'm looking for a timmer or timing circuit for a start of day/break/lunch/end of day bell.What is needed is a timmer that will ring the bell at the start of a period and ring again at the end of the period.The bell system already exsists and the owner does not want to replace it. Thank You Patrick S Kennedy Natco Industries West Warwick RI
Craig	Time Delay Relay II	Monday, October 27, 2008 11:38:18 AM
I am building a component that needs to activate a 12vdc 2amp solenoid for 2 or 3 seconds after a trigger switch has sent a signal. The trigger switch is human activated and will not stay open for the full 2 or 3 seconds. Is there a simple circuit for this operation that you know of?
Mauricio	Time Delay Relay II	Wednesday, October 08, 2008 8:00:47 AM
Hi there. I want to make a paintball 'bomb' that after 10 min activates the relay, which is connected to an alarm siren, but also 1 min from the end (at 9min.) it activates another siren, a warning siren... I already have the sirens. I also wanted a beep sound every second so that the bomb can be traced. I don't mind having 3 different circuits but need help to make them... Been trying to but the 555 timer is on at the start but the 4011 might work... Thanks in advance
anonymous	Time Delay Relay II	Friday, September 19, 2008 9:46:18 AM
te first time you switch S1 on in works ....but te second time te circuit doesnt works as it should ...te capacitor beeing carhged from the first time ...there will be no delay on te second push of S1 ( excuse my english :D )
Steve	Time Delay Relay	Saturday, May 31, 2008 4:22:47 AM
With reference to the Time Delay Relay page, if activated (by S1), the circuit should keep the relay on for the fixed time, say 20 seconds. However, after it switches off at the end of the first 20 seconds, it is not clear whether the relay will switch on again, i.e. S1 continues to be active.
Genlock	Time Delay Relay II	Wednesday, May 21, 2008 10:16:25 AM
Can a 555 timer be used to delay the output for 1 second after the footswitch is actuated?If so how is it configured.
Genlock	Time Delay Relay II	Wednesday, May 21, 2008 10:13:38 AM
I need to trigger an X-ray tube 1 sec after an imager and disconnect when the switch is open.I'm using a footswitch.I figure 1 mega ohm and 1 microfarad cap should give me 1 second.It may need to trigger up to 120 volts ac by relay.Will your circuit do this for me and do you have any suggestions?