The ac to dc power supply has two main functions: first, to convert alternating current (AC) into direct current (DC), which is filtered and supplied to the load or to the inverter; second, to provide charging voltage to the battery. Therefore, it also acts as a charger at the same time.

When the ac to dc power supply stator coil induces alternating current, it goes to the rectifier diode, and the positive electrode begins to flow through the upper diode, and the lower diode cannot pass. After the voltage output, it reaches the positive pole of the battery, then returns to the negative pole, returns to the rectifier diode through the negative pole of the generator, and finally returns to the negative pole of the stator coil. formed a loop.

The alternating current is generated by an alternator. During the power generation process, multiple pairs of magnetic poles are evenly distributed on a circle at a certain angle, so that each coil cuts the magnetic field lines during the power generation process. The voltage and current generated by the cutting of the magnetic line of force are changed according to the chord law, so it can continuously generate a stable current.

The frequency of ac to dc power supply alternating current is generally 50 Hz, that is, it changes 50 times per second. Of course, there are other frequencies. For example, there are square waves, triangles, etc. in electronic circuits, but these waveforms of alternating current are not produced by conductors cutting magnetic lines of force. It is generated when the capacitor is charged and discharged and the switching transistor is working.

The direction of ac to dc power supply direct current does not change with time. Usually divided into pulsating direct current and steady current. There is an AC component in the pulsating direct current. For example, the voltage of about 300 volts in the power circuit in the color TV is the pulsating direct current component, which can be removed by the capacitor. Steady current is ideal, with the same magnitude and direction.