re help with ultra long timing in article pqu pmu sunb ocs mq edu au johnh macadam mpce mq edu au john haddy writes in article c wi g a athena cs uga edu mcovingt aisun ai uga edu michael covington writes don t use big capacitors they are unreliable for timing due to leakage true especially for electrolytic capacitors at high temperature instead use a quartz crystal and divide its frequency by times or something like that wouldn t a crystal be affected by cold my gut feeling is that as a mechanically resonating device extreme cold is likely to affect the compliance terminology of the quartz and hence its resonant frequency low power quartz oscillators are usually khz and these have significant temperature drifts which one doesn t often notice while wearing the watch on one s wrist low temperature sensitivity is available in other crystal types which unfortunately are larger and higher frequency mhz or so and take more battery power programmable timers might be less accurate but they are more power stingy than suitable crystal oscillators john whitmore
