The role of the regulator is the discretion of the generator voltage to control the excitation circuit on and off.
1 on both ends of the excitation circuit regulator series small bulbs, brought to detect a 0 to 30 v voltage, by adjusting voltage, observe bulb light out the situation to judge the stand or fall of regulator.(such as 12 v generator regulator, when the voltage up to 14.5 + _0. 25 when light bulb will go out.
2 regulator has a very important internal electronics MOS tube, use multimeter can also measure of judgment.
