alkaline battery charger protection

[daguuy]

i saw afroman's page about recharging alkaline batteries and i have a bunch of dead alkalines lying all over the place so i made one and it worked i charged a 9v a little just to see if it works and the formerly dead battery realy zapped well. it was only charged up to around 6.5v in 2 hours because i wasn't really expecting it to work but now that it does, i want to be able to charge all the way without risking badly damaging my batteries. here's my questions:
1. what should i add to this diagram to make it stop charging when the battery is fully charged? i'd prefer just very basic stuff like resistors/transistors/diodes/caps or anything else i could easily get from some old junk
2. what do alkalines do when they're fully charged but the charger doesn't stop charging? does the chager just cram in more and more power until the battery pops or the does the battery start resisting the charge current and pop when it can't resist it anymore or what? (if it's the ladder i think i could just ad a few transistors to stop the charger but i'm not sure)
3. do transistors drop voltage?

[JackFrost22]

Uh...I was actually writing up my own with a meter that would shut off the circut when the voltage was met. Transistors osilacte and amplify they do not drop.

[G-force]

I wouldn't do that, really. Have you seen Gamelvers GCp? That's what can happen when you overcharge batterys. And overcharging batterys that aren't ment to be charged in the first plae is just asking for trouble.

It's a neat experiment, but I wouldn't practice it.

[daguuy]

After two full days of charging the AAs eventually popped open making a fizz noise, and leaked 3 drops of weak acid that was easily cleaned up with my bare hands. The experience was about as life threatening as a squirrel urinating on my lawn.

i dunno, squirrel's urinating on lawns is pretty lethal. alkalines aren't explosive like lithiums or toxic as "real" rechargables. the worst that could happen is a little leak