BFL13 wrote:
Yes it is sort of complicated till you do it in real life. Switch A makes it a typical three stage converter and if you monkey with the pot with the switch set to the left, it will change all three voltages at once. You can restore that to original though.
The real benefit is as a singe voltage manual charger with switch A to the right, set to any voltage you like with the pot B.
Maybe not a perfect solution, but much better than most other "smart" chargers which have no manual mode !
And the price is reasonable.