The workings of the Federal Reserve are about as obscure to most Americans as the back side of the moon. The trouble is that with the economy devastated by high interest rates, businesses going bankrupt and 12 million people out of work, it matters a whole lot more.

Sunday night in a documentary, "The Money Masters" (Channel 7 at 7), ABC News does a fine job of illuminating the nation's central bank, its immense power and some of the consequences of trying to fight inflation solely through tight money and high interest rates.

Yale economist James Tobin, a Nobel laureate, sums up the Fed's power: "What they do has more impact on the economic outcomes that matter to most people in this country and everywhere than any other policymakers in Washington or elsewhere. Congress or the president."

Three years ago, most Americans probably would have scoffed at such a claim. After being asked to pay 18 percent interest rates for a home mortgage or more than 20 percent for a personal loan, or after being laid off at a lumber mill or yard because no one is building new houses because no one can afford mortgages, the nation has learned what the Federal Reserve can do.

But that is not the same thing as understanding it. ABC's economics editor Dan Cordtz evidently does. In dealing with economic issues, television rarely explores their complexities and nuances, such as the interconnections between domestic policies and economic developments abroad.

"The Money Masters" does all that, tracing, for example, the way in which high interest rates in the United States helped cause high interest rates and recessions in both industrial and developing nations. And it raises the possibility of an international financial crisis, and describes in broad terms what that would mean for some American banks -- failure -- and why that matters -- more unemployment.

"The international financial situation, I think, was never at such a difficult point as it is now," says the former head of the West German central bank, Otmar Emminger.

And MIT economist Lester Thurow explains, "If these countries should collapse it would make life more miserable for Americans . . . in two ways. One, we're selling some products to these countries and when they economically collapse we will quit selling those products, and the people who make those products will become unemployed . . . Second, if these countries collapse, because the banking system would lose money, the banks would become much more cautious on lending. That means if you wanted to get a loan, maybe you wouldn't get a loan because Mexico had gone broke."

If the documentary has a serious fault, it may be that it tries to cover too much ground and sometimes fails to drive home the points it makes in passing. While indicating that inflation can be painful, the program does not discuss the speculative fever that gripped the nation back at the end of 1979 or the serious weakness of the U.S. dollar, two of the reasons chairman Paul A. Volcker set the Fed on a new course.

Nor does "The Money Masters" remind us of the rosy promises of monetarist economists such as Milton Friedman, another Nobel laureate on the program, and President Reagan, that slowing down the growth of the money supply would reduce inflation without large increases in unemployment.

But it does raise the right question: Is it time or past time for the Fed to ease its policy even more than it has in recent months, so that interest rates can continue to come down? Volcker, whose cigar and presence pervade the program, argues not. Tobin and Thurow declare yes.

"The Money Masters" is too well balanced to dictate its answer to the viewer. But it does offer us Wanda Sloan, who was working at the Acme Boot Factory in Gallatin, Tenn., until it closed in August.

"I kept thinking that Wanda can get a job," she says wistfully. "But Wanda can't get a job because there's no jobs out there. My family's my most concern . . . Where is the money coming from if there's no jobs out there to find?"