In the computer, the chip itself does not usually have a clock signal source, so a dedicated clock circuit must provide the clock signal. Quartz Crystal OSC is one of the most commonly used clock signal oscillation sources. The reason why a quartz wafer can be used as an oscillator is based on its piezoelectric effect: applying an electric field to the two poles of the wafer will cause the crystal to be mechanically deformed; when an alternating voltage is applied to the quartz wafer, the crystal will be Produce mechanical vibration, while mechanical deformation vibration will produce alternating electric field. Although the voltage of this alternating electric field is extremely weak, its vibration frequency is very stable.
Since the birth of the PC, a 14.318MHz quartz crystal oscillator has been used as a reference frequency source on the motherboard. In addition to this 14.318MHz crystal on the motherboard, you can also find a 32.768MHz crystal, which is used in the real-time clock (RTC) circuit to display accurate time and date. After initialization, pulses are sent out at approximately 18.2 times per second, and these pulses are calculated by the operating system to form the BIOS clock count. By being powered by the BIOS battery, it still runs normally after shutdown. This is why we turned off the power, and the correct time will still be displayed when it is turned on the next day.
