| 摘要 |
<p>In a protection circuit for a plurality of fans, an element is associated with each fan. The impedance or the current value of the element indicates the operation condition of the fan. For example, the impedance or the current value may be low if the fan is operative or functioning normally, and high when the fan is inoperative or functioning abnormally. The elements are arranged in parallel between two conductive lines. A detection circuit determines the total impedance or current value between the two lines. If the total impedance or current is not within a predetermined range which indicates that all fans are operating normally, at least one of the fans functions abnormally. The number of lines required to convey the operation status of the fans to the detection circuit is only two and does not depend on the number of fans involved.</p> |
