Can I use Nickle-Cadmium (NiCd) rechargable batteries instead of NiMH?
— NiMH batteries are fine since most have a mA-H rating of greater than 1000. NiCds with at least this rating should be ok as well, but the more common 450-600 mA-H types will see a somewhat higher than usual charge current. That being said, they can probably be used if you limit charging times to no more than 5 or 6 hours to minimize long term overheating. 5) How low can the batteries (or external source) go before the unit stops operating? — The Micro908 can operate on a power source (batteries or external) as low as 9V-or-so. Below this point, the 8V voltage regulator on the DDS Daughtercard will start to be affected, the DDS-generated RF signal will degrade, and the erroneous/erratic readings will be seen.. 6) Maximum Supply Voltage — The highest external voltage source you should use is 16V. Some walwarts (or AC adaptors in general) produce a much higher voltage that could cause problems longer-term with your Micro908. A quick and easy check is to power the unit with your AC ad