Sequencer, with an off period

[Purt]

Am using a 555 and 3 x 4017 + 4093 to obtain a slow "on off period" sequencer - I need a 7 second on followed by a 1 second off to repeat 19 times for a process timer.
How do I obtain the 1 s OFF (space)? The resets and rest off cct work fine

 

[djsfantasi]

Three 4017s? Don't see yet why you need so many; please tell us what they are used for and attach a schematic to your response. I would use one 4017, wired to reset on count 8. Then, outputs 0 to 6 would be diode ORed as your on cycle and output 7 would be your off cycle, when clocked by a 1Hz source.

 

[Purt]

dj
This is the front end of a circuit that each clocked output will drive one power and one standard mosfet in an on/off sequencer for independently switching/sequencing some control cables.
As you can see by my profile I have not used this mode of electronics for some years now! any help on expanding your thoughts much appreciated
Purt

 

[crutschow]

As usual, post your circuit diagram, so we can know what you are talking about.

 

[Purt]

Thanks Cruschow
Not familiar with this site
Can provide you a pi. image of the cct to date if you can tell me how?
Thanks
Purt

 

[AnalogKid]

Three 4017s? Don't see yet why you need so many; please tell us what they are used for and attach a schematic to your response. I would use one 4017, wired to reset on count 8. Then, outputs 0 to 6 would be diode ORed as your on cycle and output 7 would be your off cycle, when clocked by a 1Hz source.

Actually, you can skip the giant OR. If you look at just Q7, it is down for 7 seconds and up for 1 second. That is the required output timing with no gating. Depending on what the output is used for you might need to invert it, but that's all. Plus, you won't have the metastable dips in the output of the OR gate caused by non-synchronous switching of the counter outputs.

ak

 

[alec_t]

If you can tolerate some inaccuracy in the timing you could use one gate of the 4093 to make an 8 sec period oscillator with a 7:1 duty cycle and eliminate a 4017.