faunt@spar.UUCP (05/12/87)
I wish to use the AC adapter for my portable CD player to charge a set of nicads in the battery case of the player since I want to use the player on the aircraft while travelling without spending a fortune on disposable batteries, but would rather not carry a separate charger. I figure I have 9V (more or less) DC on a plug and an identical plug connected to the 6 C cells in the battery case. All I need, I think, is a current regulator between a pair of jacks. I'm considering using the Radio Shack high capacity nicads, which suggest charging at 200 ma for 14 hours for a full charge. I've not measured the actual voltage output of the AC adapter at a 200ma load, but I suspect it's at or over 9V. I guess I could, perhaps, use a "universal" adapter that might provide 12v for charging, but that would require making sure that the switch was in the 9V state for operating the CD player, and would be less than foolproof. The battery pack would actually be 8.4v, of course. It's been a while since I looked at this kind of analog circuitry, so I'm not sure if this would work. Would one (or more) of you nicad and analog circuit experts out there think about this, and let me know if this makes sense, and point me at references for this stuff (or send a design). Thanks ...!ihnp4!{hplabs|decwrl}!spar!faunt faunt@spar-20.arpa