When a crystal unit is actuated as an inductive reactance in an oscillation circuit, the relationship between crystal unit and oscillation circuit is shown in Fig.6.To improve the starting conditions of the oscillation circuit, it is preferable to increase the value of negative resistance -R which parameter of the oscillation circuit .The starting conditions will become worse if a circuit without much allowance in negative resistance (less negative resistance )is combined with a crystal unit having a larger resonance resistance. The oscillation circuit should be designed to a goal such that the value of negative resistance is 5 to 10 times the resonance resistance. It is also necessary that the center value of load capacitance (to determine the absolute value of oscillation frequency )and the variable range (fine adjustment range of oscillation frequency) are maintained at the optimum values in the oscillation circuit.



在振荡电路中，石英晶体谐振器作为感抗被使用。石英晶体谐振器和振荡电路的关系如图 5 所示，为提高振荡电路中的起振条件，须提高振荡电路中的负阻抗，而电路中没有足够的负阻抗偏差，则较难起振。在振荡电路中负阻抗的值应达到谐振阻抗的 5-10 倍。在振荡电路中，负载电容的中心值（其决定谐振频率的绝对值）和其变化范围（谐振频率的良好调整范围）应保持在最佳值。