> I must power a datalogger (16F84, 24LC256, LM75, IR LEDs, TSOP17 IR
> detector) from NiCad or other rechargeable batteries. Current use ~ 3 mA,
> must run for 14 days, so 2AH is plenty. But how should I get the
> right Vcc?

Consider using a MAX757 boost circuit. You can set it to output 5V. It can
be fairly efficient (this depends on the capacitor and inductor you use - up
to 85% efficiency), and the battery voltage can drop under 1V, so you will
have good usage of the batteries, before needing to recharge them.

Bane Jakovljevic
www.celestialhorizons.com

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