是晶体的匹配电容,容量一般在 20 ~ 30pF 。这种接法是并联振荡电路,晶体呈现感性,与电容器构成电容三点式振荡电路。
http://baike.baidu.com/link?url=ZuNneoZOU0bdWX9ItckGHBg-UQEHXrBB5_yLSMY8hkoGpBDNsBMwojph-y3hwACEWFpciyqmKT_pGOf10HhhrOK7NcUVM9Pcrj3_z4HrYO5lvU0g2QVzCzOCqaM_U4i1zQpSzREU-tLifoC7525U_PHtmPZQvfXl47KdjZp_VIxvfPHnEhCqfyNubJrK9LXY