Question

what is the LT supply configuration?

Answer 1

LT power supply.

This is providing low voltage but high current. Because for evaporation of any metal you need a high current (20 to 70 Amps), to melt the evaporation material kept on the boat. So you need a LT power supply.

It basically consists for a step down transformer, which produces a low voltage and a high current at the secondary, and you you evaporation electrodes where you connect the tungsten filament are connected to this output.