SAN FRANCISCO — When Apple wants to make a big splash, it returns to its history.

Thirty years ago at the Flint Center for the Performing Arts, a roomy auditorium in Cupertino, Calif., Steven P. Jobs introduced the original Macintosh. On Tuesday, Apple will return to the center to unveil a set of long-anticipated products: two iPhones with larger screens and a wearable computer that the media has nicknamed the iWatch.

The so-called smartwatch will be the first brand-new product unveiled under Timothy D. Cook, Apple’s chief executive, who took the helm three years ago, shortly before Mr. Jobs’s death.

It is expected to come in two sizes and combine functions like health and fitness monitoring with mobile computing tasks like displaying maps. It will have a flexible screen and, like the new phones, will support technology that allows people to pay for things wirelessly.

“I believe it’s going to be historic,” said Tim Bajarin, a consumer technology analyst for Creative Strategies who attended the original Mac event in 1984. He added, “The design of this product is all Tim’s fingerprints."Apple, which is highly secretive, has not officially commented on any of the new products. But multiple employees of Apple and its partners who were briefed on the products shared some details on the condition that they not be identified.