THE electronics industry is transforming bulky encyclopedias, dictionaries, and even the Bible into slim, portable computers that can sit in the palm of a hand."These devices are true consumer hand-held computers," says Roger Lanctot, research director at Personal Technology Research in Waltham, Mass. "They are at the very entry level of a modest explosion that's taking place in hand-held computing." In 1990, sales of all hand-held, consumer-oriented electronic products totaled $7.4 million; that figure is projected to be $12.5 million by 1994, according to Personal Technology Research. Relatively new technology in the areas of low-power consumption and data compression make many of these compact products possible. "Fundamentally, it's a lot of grunt work in getting that data compressed," Mr. Lanctot says. Some of the commercial applications of the shrinking electronic components are showing up in notebook-size computers carried by delivery people. Many United Parcel Service and Federal Express employees now tote compact computers on their routes to help keep records and cut down on paperwork. Growth in hand-held computers is "taking place more or less quietly in commercial applications and industrial ... or professional markets," Lanctot says. But the technology also is allowing for portable, electronic versions of a range of reference materials and organization tools for students and businessmen. Franklin Electronic Publishers in Mount Holly, N. J., has converted the Concise Columbia Encyclopedia from print to a hand-held electronic version. The user-friendly reference weighs only 12 ounces and features cross-referencing, a thesaurus, automatic spelling correction, and an educational quiz game. Suggested retail price: $399.95. Dictionaries and spell checkers - which sell for considerably less - are the fastest growing area of the electronic reference category, according to Milton E. David, chief executive officer of Franklin, which has about 70 percent of this market. Also on the market: translators that can "speak" words or phrases in several languages, currency converters, calendars, Rolodexes, datebooks, and personal organizers. SelecTronics Inc. of Pittsford, N. Y., sells electronic reference products through Amway, a network marketing organization. Franklin and SelecTronic are currently the only manufacturers of electronic encyclopedias. For the Christmas season, Sony Corporation is expected to unveil the Data Discman, a hand-held computer that uses different disks allowing the 24-ounce machine to serve as an encyclopedia one moment and a dictionary the next. It's expected to sell for about $450. In October, Oregon Scientific of Beaverton, Ore., will introduce a desktop calendar and organizer that uses some of the latest technology. The $600 "AXXESS" machine is connected to a telephone and can store up to 1,000 business cards electronically. A computer screen can be programmed to automatically dial telephone numbers with a touch of the finger. Simply press a name or a preprogrammed word that appears on the machine's screen. Experts predict that bilingual electronic dictionaries will boom in the future. "There are increasing varieties of devices out there with five or six or more languages built into them," Lanctot says.