Power-on time delay relay circuit - Electronic Circuits Projects Diagrams Free

themikestar · 25th October 2003, 02:41 PM

i need a circuit so that when power is applied to it the a relay will close after about 10 secs and stay on. It should be a very simple circuit but i have tried 3 circuits now and none have worked.

cir1 = worked perfectly for a led but outputs a maximum of 5v (not enough to drive a relay)

cir2 = i thought i had it working , but all it does now is outputs 10v straight away there is no delay.

cir 3 = i couldn't get any 2n3053 so i used a 2n2222, when i use a led as an idicator it is very dull until i tap the 47k resistors led with metal and then it brightens (there are no loose connections), so basically it doesnt work either.

can someone please tell me how to get any of these ciruits to work or could someone suggest another circuit to try.

please help

Sebi · 25th October 2003, 03:32 PM

Try this circuit...

themikestar · 27th October 2003, 12:01 PM

the circuit only works when i run it from 2-6 volts, i need it to run from 9v how can i drop the voltage down to around 5 or 6 volts, itried using resistors but it didn't work. cani use zeners or something ??.

Noggin · 27th October 2003, 01:52 PM

7805 or Zener/Resistor? How much current do you need from the 5v?

themikestar · 27th October 2003, 10:35 PM

i only need ennough current to run the timer circuit and a very small 5cv relay.

is this circuit how i do it, if so what size should the resistor be ??

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25th October 2003, 02:41 PM	#1
themikestar	Power-on time delay relay circuit i need a circuit so that when power is applied to it the a relay will close after about 10 secs and stay on. It should be a very simple circuit but i have tried 3 circuits now and none have worked. cir1 = worked perfectly for a led but outputs a maximum of 5v (not enough to drive a relay) cir2 = i thought i had it working , but all it does now is outputs 10v straight away there is no delay. cir 3 = i couldn't get any 2n3053 so i used a 2n2222, when i use a led as an idicator it is very dull until i tap the 47k resistors led with metal and then it brightens (there are no loose connections), so basically it doesnt work either. can someone please tell me how to get any of these ciruits to work or could someone suggest another circuit to try. please help Attached Thumbnails

25th October 2003, 03:32 PM	#2
Sebi	Try this circuit... Attached Thumbnails

27th October 2003, 12:01 PM	#3
themikestar	the circuit only works when i run it from 2-6 volts, i need it to run from 9v how can i drop the voltage down to around 5 or 6 volts, itried using resistors but it didn't work. cani use zeners or something ??.

27th October 2003, 01:52 PM	#4
Noggin	7805 or Zener/Resistor? How much current do you need from the 5v? __________________ A rectangular bear is just a polar bear after a coordinate transform. -- I dunno who. A recent study shows that research causes cancer in rats. -- I dunno who said that one either.

27th October 2003, 10:35 PM	#5
themikestar	i only need ennough current to run the timer circuit and a very small 5cv relay. is this circuit how i do it, if so what size should the resistor be ?? Attached Thumbnails