A crystal oscillator can fail for a variety of reasons, but the quality of the quartz crystal materials used in manufacturing a crystal oscillator and the precision and accuracy of the manufacturing process can have a major impact on the effectiveness and longevity of a crystal oscillator. That is why the crystal oscillators found in all of SCTF electronic devices and products are held to the strictest standards for design and manufacturing. During the oscillation of a quartz crystal oscillator, the electric signal transmits from one of the two capacitors to the quartz crystal and then back to the other capacitor in a continuous loop. If the equivalent resistance of used crystal is increased due to the defect of quartz crystal and become higher than the negative resistance of oscillator circuit, the oscillation process may never even start.