I have a problem with a 32768Hz crystal. I have set it up like shown on the picture I’ve provided and I divided the frequnecy with three 4024 7-bit (÷128) ripple counters. It works but the length of the “second” is too short (i’d say maybe 900ms), I noticed it by watching obviously but confirmed it with a stopwatch… I don’t get what is wrong… I have some suspicions, though. I think the 1M resistor has got something to do with the time, because when I change its value the length of the time changes as well… That makes me ask a question: how come the frequency can be dependant on the resistor, I thought the crystal has got its natural oscillating frequency…And if you’re asking where did I get this configuration it’s from A level Electronics book.
Crystals have specific loading requirements and it looks like your circuit is making the grade for the crystal. Is this a “standard” watch crystal? If so, perhaps the following oscillator might work better: http://www.elecfree.com/electronic/3276 … h-crystal/
I don’t know much about crystal. I will try this “32.768 KHz oscillator using a watch crystal”. I’d like to understand how does the crystal physically work and also I would like to know what sort of crystal should I use in order to use the circuit I have.
okay… but does anyone know what crystal I can use in such configuration I have provided… there must be a type of crystal.
and also in the page http://www.eleccircuit.com/32768-khz-os … h-crystal/ there is a variable capacitor required… can you tell me about that a little bit… like what valuse should it be ranging between and where to get it
If you look at the link in your last post, the crystal is across the inverter, not in series with the signal. As for the cap, I’d guess a 30 or so pF trimcap. You could also just try caps around 30pF and see if things are close enough.
