Two Simple Electronic Inquiries

1) For my NOKIA cellular, I have two chargers; one heavy (obviously normal 2-coil adaptor), the other is light (electronic). The second one charges in much less time than the first. WHY?
Also can anybody give me and idea or link me to how does an electronic adaptor work?!

2) Some light systems, operates (light on) when you press the switch, then automatically turns off after a small period of time (about 10 minutes or less). What's the idea?

Thanks all

The light charger is called SMPS (Switch Mode Power Supply). It is a reulated power supply. It provides constant charging current to the battery and so it charges fatser than the bulky one. The bulky adapter does not have regulator inside and so its output voltage and current varies depending upon the charge on the battery.

The switch you are talking about is a monostable multivibrator which when triggered remains on for a predetermined period (depends upon component values used) and then turns off until re-triggered. Search google for "555 monostable schematic" for a very simple schematic based on timer IC 555.

Thanks Dude