Senator Barack Obama has three new ads up in Pennsylvania, his first on television, following two radio spots earlier this week. Senator Hillary Clinton, who leads in polls in the state, has not run any ads in the state so far.

Mr. Obama’s first spot, which runs 60 seconds, is called “Opportunity.” Made specifically for Pennsylvania, this spot is biographical and underscores the Obama campaign’s sense that he still needs to introduce himself to the state’s voters.

The second, running 30 seconds, is called “Toughest” and describes him as having passed the “toughest ethics law yet” against lobbyists and special interests.

The third spot,

also running 30 seconds and called “Carry,” refers to bipartisan legislation that Mr. Obama “carried” in the state senate in Illinois.

All the ads are running in the state’s six major media markets and come as both campaigns are stepping up already-ferocious registration drives to meet Monday’s deadline, by which time voters must be registered as Democrats to vote in the April 22 primary.

So far, more than 100,000 new voters have registered and an additional 58,000 have switched their party affiliations to Democratic, overwhelming local registration offices.

The ads, all of which emphasize that Mr. Obama has fought special interests and can work across party lines for bipartisan purposes, will augment the final registration push this weekend.

The first two ads were made specifically for Pennsylvania, while the third has run elsewhere.

In the current context — with videos appearing over and over again of Mr. Obama’s pastor, the Rev. Jeremiah A. Wright Jr., renouncing America — the ad called “Opportunity” links Mr. Obama with the American dream. It is intended as a reassuring message that he shares voters’ values and their patriotism.

“My grandfather served in Patton’s Army,” Mr. Obama says in the ad. “My grandmother worked on a bomber assembly line.”

He also says he has fought on behalf of laid-off steelworkers, a group with whom Pennsylvanians can identify, and notes that he was an organizer with “Christian” churches, another signal meant to counteract suggestions that he is not Christian himself.

Mr. Obama delivered a major speech on race in Philadelphia on Tuesday. Some analysts have said the speech may have had the unintended consequence in parts of Pennsylvania of solidifying his image as the “black” candidate in the minds of white, working-class, male voters. The new ads show him at several points talking with white, blue-collar men.