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555 as an astable multivibrator

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Another question:
How did you calculate the value of the capacitors and the resistors in order to achieve 15min on/off square wave.
Is there any formula or equation for that?

Get the datasheet, the formula for the time constants are on the sheet.
 
I get a bit anoyed here as i just wrote the whole post and could not submit while the whole tread is now incorporated in this one:mad:

please do stick with the tread if it is related and don't make otherones in other sections as it realy gets messy

I put something on paper and to give you a tip

if you put a time frame of 16 min on pin nr 15

than the frequenty doubles at every pin in this folowing order
Pin nr 13,14,6,4,5,7

this in combination with other ports it will give you the base of a blinking signal in the last 2 minutes of the time cycle (16min on pin 15)

get the data sheet for more info

sucsess
Robert-Jan
 

Attachments

  • TMP11.JPG
    TMP11.JPG
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I couldn't understand your question completely.
Is it that you want the green and red LED's to glow simultaneously, for every 4 min.
And each LED should glow for a period of 16 mins?

However whatever you requirement may be it can be acheived by simple programming.
You can take the help from any programming person.
 
As you have asked previously about obtaining an asymmetrical square wave, you can get it with 4060. You just have to make few more connnections, which would be explained in the datasheet
 
Hoi barakorit

in my schematic i draw a litle mistake that would result in some outputs going high in the down period

i changed it in the new attachment (see red circled part)

what is actualy the aplication that you want this circuitry to use for??

Robert-Jan
 

Attachments

  • TMP13.JPG
    TMP13.JPG
    201.7 KB · Views: 147
hi,
Its important to remember when using external gating on the 4060, its a ripple thru counter.
You can/will get switching 'glitches' on the gate outputs, a small R/C filter on the gate outputs, is a good idea.
 
Hi Robert-Jan
Thanks for the schematic.
In this application, a 2min On/Off square wave doesn't exist (since there is no Q11 in the 4060), but I still need this signal.
Is there any way (a circuit or a component) that generates this kind of signal from another signal in another frequency (the 1min or the 4min On/Off, for example)?
Barakorit.
 
if you tune the frequency so that the 16 minute squarewave is located on pin nr 15 than your 2 min square wave will be on pin nr 6

as you did saw on the data sheet there is one output mising in the sequence so try to put your lowest frequency on the output just after the missing one so the other are in folowing order withou interuption

to lower the frequency you can increas the capacitor value and the resistor values

sucses
Robert-Jan
 
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