Final answer:
A voltage regulator modifies the output voltage of a generator by changing the field current. This in turn adjusts the strength of the magnetic field within the generator, which determines the voltage produced.
Step-by-step explanation:
A voltage regulator controls generator voltage by changing the field current in the generator. This is because the output voltage of an electric generator is determined by the speed of rotation of coils within a magnetic field and the strength of the magnetic field itself. By adjusting the current in the generator’s electromagnet (field current), the magnetic field strength is changed, which in turn affects the voltage produced by the generator.
An easy way to understand this is through an electric generator, which contains wire loops in a magnetic field. When mechanical energy rotates these loops, an alternating current (AC) voltage is produced. If you want to regulate this voltage to a desirable constant for use, say in a home or an industry, the voltage regulator plays a crucial role.
The voltage regulator modifies the field current, effectively controlling the output voltage to a level that can be used safely and efficiently. One example given in the mentioned references is connecting a generator to an RLC circuit and measuring various electrical properties such as the rms voltage, impedance, and average power output. Another example is varying the frequency of an AC generator, which would alter the current while keeping the output voltage amplitude consistent.