Page 25 of 28 EXHIBIT A --------- Agreement of Joint Filing ------------------------- The undersigned hereby agree that a single Schedule 13G (or any amendment thereto) relating to the Common Stock of Capstone Turbine Corporation shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G. Dated: February 14, 2001 SEVIN ROSEN FUND IV L.P. /s/ John V. Jaggers ---------------------------------------- By SRB ASSOCIATES IV L.P., Signature Its General Partner John V. Jaggers General Partner SRB ASSOCIATES IV L.P. /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers General Partner SEVIN ROSEN FUND V L.P. /s/ John V. Jaggers ---------------------------------------- By SRB ASSOCIATES V L.P., Signature Its General Partner John V. Jaggers General Partner SEVIN ROSEN V AFFILIATES FUND L.P. /s/ John V. Jaggers ---------------------------------------- By SRB ASSOCIATES V L.P., Signature Its General Partner John V. Jaggers General Partner SRB ASSOCIATES V L.P. /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers General Partner Page 26 of 28 SEVIN ROSEN FUND VII L.P. /s/ John V. Jaggers ---------------------------------------- By SRB ASSOCIATES VII L.P., Signature Its General Partner John V. Jaggers General Partner SEVIN ROSEN VII AFFILIATES FUND L.P. /s/ John V. Jaggers ---------------------------------------- By SRB ASSOCIATES VII L.P., Signature Its General Partner John V. Jaggers General Partner SRB ASSOCIATES VII L.P. /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers General Partner JON W. BAYLESS /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact STEPHEN M. DOW /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact STEPHEN L. DOMENIK /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact Page 27 of 28 JOHN V. JAGGERS /s/ John V. Jaggers ---------------------------------------- Signature JACKIE R. KIMZEY /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact CHARLES H. PHIPPS /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact JENNIFER GILL ROBERTS /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact DAVID A. SHRIGLEY /s/ John V. Jaggers ---------------------------------------- Signature John V. Jaggers Attorney-In-Fact