Assuming default cookie expiration timing, a conversion (1-per-click) is recorded when:

Assuming default cookie expiration timing, a conversion (1-per-click) is recorded when: 

A) a user clicks on an AdWords ad
B) multiple conversions result from a single AdWords ad click
C) a single conversion is made within 30 days following an AdWords ad click 
D) a user visits a website within 30 days of clicking on an AdWords ad