hey all am making a clock..... and ive managed to acquire an IC. the lm8560n i've got everything else wired up and everything,the only thing that i cant figure out is the 50/60hz input so is there anyway that i can make some sort of a small board that will output a 50/60hz signal? thanx. (im thinking 555 timer)
A 555 timer is not accurate enough - you'll probably end up losing or gaining several minutes every day. The IC is designed so that you can easily derive a stable frequency from the mains (hence the 50/60Hz signal), but if you can't for whatever reason then you either need a crystal-based oscillator, and scale down the frequency.
Did you have a look at the LM8560 datasheet...? All you need is a 100K resistor and a 1nF capacitor connected to the secondary winding of the transformer and the 50/60Hz input. CD
bUT HE'S Wanting to run it from a battery. Something like a 4060 chip, which has a built-in oscillator that can be crystal-controlled, and a built-in divide-by-2-lots-of-times series of flipflops, would be OK, but I can't spot a crystal frequency to give 50Hz or 60Hz after binary division. There is a battery-backup on that chip, so maybe it will keep reasonable time from built-in bits. RTFM.
Sorry, I can't see where he's talking about battery running... 3.2768MHz Xtal with 2^16 divider gives you exactly 50Hz. Intersil used to have a chip (ICM7238?) which runned from a 3.2768MHz Xtal and had two outputs (50 and 60Hz), but it seems obsolete now (I have still one running on a self-made LED clock from 1973). The 4521 unfortunately has 2^18 as lowest divider, the 4060 has 2^14 as highest divider. A 4060 with 3.2768MHz Xtal, output after the 14th flipflop, followed by two more flipflops to obtain 2^16 divider? CD
Ah, it was his other thread on the same subject , but as the datasheet circuit shows how to tap the 50/60Hz from the psu transformer secondary I assumed he was still on the same requirement.
hey thanx for that. yup, i do want to run it off a battery,but i dont particularly wanna mess around with AC power. will see whats happening after i get my results on thurs as will have more cash on that day if all goes well so will probly end up placing a big order with RS on fri! thanx all.
