When H.M. (Mickey) Michaux Jr. came very close last year to becoming the first black congressman elected from North Carolina since 1899, it electrified black residents of the 11-county 2nd Congressional District around Durham and Rocky Mount.

Sensing a chance at victory, they had turned out at a rate higher than that of whites and put Michaux 12,000 votes ahead of fellow attorney Tim Valentine in the three-candidate Democratic primary in June.

But like many southern states, North Carolina requires a majority victory, and Michaux had won only 45 percent of the vote. In the runoff election a month later, even more blacks turned out. But, in balloting split largely along racial lines, Valentine defeated Michaux by nearly 8,400 votes. Valentine went on to win the general election.

When black political activists in North Carolina analyzed the results, they found that blacks comprise 40 percent of the population but only 30 percent of the registered voters in the 2nd District, where Operation PUSH President Jesse Jackson launched a seven-state southern voter-registration crusade Sunday.

Michaux's loss was in part a consequence of the statewide disparity in registration--66 percent for whites compared with 51 percent for blacks--that is not unusual for the 11 southern states where more than half of the nation's blacks live.

Before next year's elections, which include a challenge to conservative Sen. Jesse Helms (R-N.C.), North Carolina blacks hope to add 100,000 names to the list of 482,000 blacks now registered. That could mean 12,000 more black voters in the 2nd District, over 40 percent more than Michaux's losing margin there last year.

"There is more intensity of feeling about the importance of political participation in the black community than there has been in a great long time," said Bishop John Hurst Adams of Washington, chairman of the social action commission of the African Methodist Episcopal Church.

Ministers in the 2 1/2-million member AME church are are being directed to increase voter registration among their parishoners.

Predominantly black Greek-letter organizations such as Alpha Kappa Alpha and Kappa Alpha Psi also have voter registration "networks." Another prominent black social organization, The Links, is a member of the National Coalition on Black Voter Participation.

"It's really a time of scramble, so to speak, for many people who had taken for granted the benefits they were receiving," said Geraldine Thompson, executive director of the Atlanta-based Voter Education Project, the South's leading voter-registration organization.

"Many blacks are suddenly waking up and realizing that, though they had been comfortable, they had not arrived. They have more credit, but the bills are due, and the children don't have the college loans they had before."

The Voter Education Project, which last year registered 200,000 blacks in 11 states in four months, hopes to register an additional 1 1/2 million before the 1984 elections.

"It's a combination of the Reagan programs, what happened in Chicago in the mayoral race , plus the feeling that things are really getting bad," said Georgia state Sen. Julian Bond, who is president of the Georgia NAACP. "There are not droves and droves of people standing in line signing up. But they're easier to sign up now."

Ben Ruffin, a former community activist in Durham and now a special assistant and senior policy adviser to North Carolina Gov. James B. Hunt (D), said that black victories and near victories have led to more political enthusiasm and activity.

"They are running now because there is a chance to win," Ruffin said. "Once the people run, the churches and the fraternities on down the line get involved."

Half of the nation's estimated 5,000 black elected officials are in the South. North Carolina, which had only five black judges and 14 black county commissioners five years ago, now has 19 judges and 40 commissioners, including nearly half a dozen commission chairmen.

Mississippi has 394 black elected officials, more than any other state. But they account for 6 percent of municipal officials in a state whose population is more than 30 percent black. Ninety-one percent of Mississippi's whites are registered to vote, compared with 64 percent of blacks.

"It's political and economic intimidation. That's what it comes down to," said Louis Armstrong of Jackson, Miss., chairman of the Operation PUSH board there.

"You say, 'You don't have things like poll tax any more . . . ,' " said Gracia Hillman of the Washington-based National Coalition on Black Voter Participation. "But you've got these other kinds of laws on the books that make it damned difficult to do any serious voter registration."

Most southern states do not permit post-card registration. And many are reluctant to send deputy registrars to churches or other places where large numbers of blacks can be registered. The sole registration offices often are in distant courthouses.

"Our people just are not going up there," said Jerry Wilson, director of the voting rights project for the Southern Regional Council, a civil rights research organization in Atlanta. "There's just too much intimidation and past problems with the courthouse." In some instances, Wilson said, whites have established at-large election systems that deny blacks proportional representation.

In other instances, Thompson said, black voting strength has been diluted through gerrymandering. Registrars have changed polling or registration places without publicizing the changes, she said, and set irregular registration times or kept registration books in their homes.

Efforts to increase voter registration are largely voluntary, with coordinating groups, such as the Voter Education Project, offering minimal financial assistance. It plans this year to help 100 registration projects in 10 states on a budget of $500,000 to $800,000, Thompson said.

The efforts to register more black voters come as the nation prepares for a presidential election in which increased delegate strength and earlier primaries have placed the South in a key position.

The 11 southern states will send 930 delegates to the Democratic National Convention, with 1,962 delegate votes needed for nomination. They also account for 138 votes in the Electoral College, with 270 needed to become president.

The Joint Center for Political Studies has found that in six of the states--North Carolina, South Carolina, Virginia, Alabama, Arkansas and Tennessee--the number of unregistered blacks exceeds the Republican margin of victory in the 1980 presidential election.

"It would make a tremendous difference if you got those voters out," Bond said. "It makes the South more important . . . . It adds to the mix a hefty ingredient of what most of the Democrats feel they can get anyway."