[UNIVERSAL BATTERY CHARGER/DISCHARGER(PLZ help)]

1)When you push the button how it works?
I need descreption because my teacher will be asking a lot...;)
What you regulate with trimmer?
I have a lot of questions...
this is the manual of kit
http://www.velleman-kit.com/downloads/0/illustrated/illustrated_assembly_manual_k7300.pdf
Plz check it out and tell me about it.
THANKS A LOT!!

[UNIVERSAL BATTERY CHARGER/DISCHARGER(PLZ help)]

Hi!!I'm new in this forum(and electronics!!)
I want your help to do my homework.....
I bought a UNIVERSAL BATTERY CHARGER/DISCHARGER kit
this is the kit's diagram


I have a few questions.....
Can you help me?