Question for electronics experts (re: flip flop circuit using Cmos 4060B)

[Savvypro]

I’ve been looking to build a timer circuit for a test device, all the circuit has to do is turn a DPST (Double pole, single throw) relay on and off every 15 minutes.

I came across the following site, which has a circuit that looks like it does what I want, what I’m not 100% cretin about is what pin to use on the Cmos 4060B:

site: 24 Hour Timer

I’ve used the email at the top of the page to contact the author, but have had no reply.

From the table for circuit {1}, setting the range connection to pin 13 looks to be what I’m looking for.

Could someone who has built similar type circuits or has used the 4060B confirm if I could get the correct 15 min on/off on that pin.

Or would I be best setting it to some other pin which has a smaller range with 15 mins being in the middle somewhere.

[gyula]

Hi,

Yes I agree on using Pin 15 with those RC values for the oscillator parts.

Here is some more useful explanation on the CD4060:
Electronics timer by CD4060

you now understand that an RC oscillator frequency is divided down to the needed low frequency, so the inverse of the low freq is the time delay you need.

Now if you need higher precision for the 15 minutes, you may wish to run the oscillator at a higher frequency (not at the few Herz it is shown) and use higher divison number (higher than ÷512 at Pin 15) then you are ok now to proceed.
The advantage in precision comes from the fact that an RC oscillator runs with nearly the same stability at some hundred Hz or at a few kHz wrt the 2-3 Hz and dividing the higher freq to the same low freq the drift gets also divided down, hence your longer term 15 min accuracy can improve.

rgds, Gyula

[Savvypro]

Hi,

Yes I agree on using Pin 15 with those RC values for the oscillator parts.

Here is some more useful explanation on the CD4060:
Electronics timer by CD4060

you now understand that an RC oscillator frequency is divided down to the needed low frequency, so the inverse of the low freq is the time delay you need.

Now if you need higher precision for the 15 minutes, you may wish to run the oscillator at a higher frequency (not at the few Herz it is shown) and use higher divison number (higher than ÷512 at Pin 15) then you are ok now to proceed.
The advantage in precision comes from the fact that an RC oscillator runs with nearly the same stability at some hundred Hz or at a few kHz wrt the 2-3 Hz and dividing the higher freq to the same low freq the drift gets also divided down, hence your longer term 15 min accuracy can improve.

rgds, Gyula

Gyula,

Thank you for your response as well as the link.

Not sure if you did a typo error when you mentioned pin 15:

Yes I agree on using Pin 15 with those RC values for the oscillator parts.

Going by the table for circuit {1} pin 15 is shown as having a range of 30min to 90 min. Just want to make sure I'm reading you correctly.

[gyula]

Yes, I mistyped, sorry for that. Correct Pin number is 13 of course. Was thinking on the 15 minutes....

Gyula