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Repeating timer help !

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yusuf

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Hi Guys !

I want to make a repeating timer which can give 10minutes on and 30 minutes off...

Thanks in advance ...
 
Then you need two timers, one 10 minute and one 30 minute. At the end of the 10 minute timer it resets itself but also starts the 30 minute timer. At the end of the 30 minute timer it resets itself and starts the 10 minute timer. You also need an initial start for the 10 minute timer, normally a push button.
 
Thanks moffy !!
Can you give circuit diagram if possible friend !

:)
 
Hi Guys !

I want to make a repeating timer which can give 10minutes on and 30 minutes off...

Thanks in advance ...
Are you still going on with this overly complicated pump timer?
 
a 555 timer operated in astable mode can do this stuff.
 
a 555 timer operated in astable mode can do this stuff.
Not cheaply and reliably on its own (i.e. without having to drive a counter chip). It's not good for delays greater than a minute or two unless you use an expensive very low leakage timing cap.
 
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basically you need a multivibrator to give a pulse in 10min or change the state every 5 min, then use a 4017 counter to be clocked from this. set and reset a flip flop using appropriate output of the 4017 counter so that the flip flop will give an out put 10min high and 30min low.
 
thanks to all friends...
this thread has being now solved.. :)
 
@4pyros
Re the circuit you linked to, even at the minimum (5 min) setting it is using an 8.2 meg timing resistor. That implies an intended cap charging current of ~ 1uA. At the 30 min setting the intended current is ~ 150nA !
I refer you to
**broken link removed**
That indicates that many of even the 'best' tantalum capacitors have typical leakage currents > 1uA at their rated voltage. However, if the leakage current at a lower voltage is greater than the intended charging current in the timing circuit then the cap simply won't charge. It makes me wonder if that circuit can actually work, or perhaps it's an 'ideal' one?
 
@4pyros
Re the circuit you linked to, even at the minimum (5 min) setting it is using an 8.2 meg timing resistor. That implies an intended cap charging current of ~ 1uA. At the 30 min setting the intended current is ~ 150nA !
I refer you to
**broken link removed**
That indicates that many of even the 'best' tantalum capacitors have typical leakage currents > 1uA at their rated voltage. However, if the leakage current at a lower voltage is greater than the intended charging current in the timing circuit then the cap simply won't charge. It makes me wonder if that circuit can actually work, or perhaps it's an 'ideal' one?
That's a good question. I never made it. I dont know its origin but its all over the net. I found it in a image search and it must have been on ten sites. It may be no good, I dont know.
I have been looking at some timing chips that may help the OP. Look up CD4536 and CD4541. Thay seem to be old but still avalible.
 
Thanks friend for your reply.. I want to use two CD4093 timing IC.. For 10 minutes On and 30 minutes off.. :)
 
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