Stop in for a cup of coffee

It’s really not hard to understand. Since voltage drops with temperature because of increased resistance, electronic alternators employ NTC thermistors to provide resistance at lower temperature that is reduced as the temperature increases such that the output voltage remains constant across the entire operational range.

The principle is simple. If resistance is high at the upper temperatures, then increase voltage output at the source and add resistance at lower temperatures that decreases with temperature so that across the thermal range it stays even to the operational system.

Voltage stabilization 101.