You can charge NiCad in a charger designed for NiMH, but you
CANNOT charge NiMH in a NiCad only charger. While the
charging regimens are similar, the deltaV termination method
for NiMH requires greater precision not present in the NiCAD
charger. NiMH chargers can also use deltaT termination methods.
The end result of charging NiMH in a NiCAD charger is likely to
be overcharging, overheating and venting. All bad for the battery.
rechargable alkalines require a completely differnt kind of charger.
Sure they can. But you had better monitor them very carefully as the end
point detection process is slightly different for Nicad and NiMH. If you
want your rechargeable batteries to last a long time then get a battery
charger that switches itself off for the correct type of battery.
As for alkalines, well, same applies except that the charging end point
is quite different to Nicad and NiMH, as is the final charged voltage.