Card edge connector

A card edge connector for establishing an electrical connection between a daughter card and a printed circuit board, the card edge connector comprising:

• an insulative housing including a card receiving slot, a plurality of contact receiving cavities opening to the slot, and a plurality of pre-load portions each being provided between the slot and a corresponding cavity;
• a plurality of first contacts each having a spring portion, a tail and an intermediate retention portion, the retention portion being secured in a corresponding cavity of the housing, the spring portion and the tail extending from opposite edges of the retention portion, the spring portion forming a contacting portion extending into the slot of the housing, the spring portion having a free end bearing against a corresponding pre-load portion of the housing;
• and
• a plurality of second contacts each having a spring portion, a tail and an intermediate retention portion, the retention portion being secured in a corresponding cavity of the housing, the spring portion and the tail extending from opposite edges of the retention portion, the spring portion having a contacting portion extending into the slot and an S-shaped portion interconnected between the contacting portion and the retention portion, the S-shaped portion forming a turning point opposing the retention portion, the spring portion having a free end bearing against a corresponding pre-load portion of the housing;
• wherein the contacting portions of the first and second contacts apply substantially the same normal force to the daughter card while the spring portion of the second contact moves downward with respect to a corresponding pre-load portion of the housing to reduce an effective length thereof until the turning point of the S-shaped portion of the second contact abuts against the retention portion of the second contact during insertion of the daughter card into the connector.