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Description For:

Programmable Timer For Long Intervals

Disclaimer

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c3_rb.gif (171 bytes)

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By using an RC oscillator and a programmable divider, this counter can run for hours. An interval oscillator runs at a frequency given by (see schematic):


f = 1     and R3~2R2
2.3 R4 C2

By using, for example, R4=390 K and C2 = 10mF and R2, the oscillator can run at 0.1 Hz. Divided by 65536, this is a cycle of approximately 655 000 s (182 hours, slightly more than a week).
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