<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED BALANCE SHEETS OF TELEGEN CORPORATION AS OF DECEMBER 31, 1998 AND
1997 AND THE CONSOLIDATED STATEMENT OF OPERATIONS FOR THE YEARS ENDED DECEMBER
31, 1998 AND 1997 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>

<S>                             <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1998             DEC-31-1997
<PERIOD-START>                             JAN-01-1998             JAN-01-1997
<PERIOD-END>                               DEC-31-1998             DEC-31-1997
<CASH>                                              14                 275,891
<SECURITIES>                                         0                       0
<RECEIVABLES>                                        0                  66,000
<ALLOWANCES>                                         0                  66,000
<INVENTORY>                                          0                  75,760
<CURRENT-ASSETS>                                    14                 610,249
<PP&E>                                       1,106,669               2,253,008
<DEPRECIATION>                                 672,772                 706,825
<TOTAL-ASSETS>                                 433,911               2,231,614
<CURRENT-LIABILITIES>                        3,675,215               2,901,366
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                    23,385,796              16,031,336
<OTHER-SE>                                (22,493,460)            (17,501,088)
<TOTAL-LIABILITY-AND-EQUITY>                   433,911               2,231,614
<SALES>                                         57,900                 463,486
<TOTAL-REVENUES>                                57,900               1,038,402
<CGS>                                          264,578                 234,292
<TOTAL-COSTS>                                  264,578                 328,085
<OTHER-EXPENSES>                             3,333,676              11,431,110
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                           1,115,493                  89,364
<INCOME-PRETAX>                            (4,991,562)            (10,455,911)
<INCOME-TAX>                                       800                       0
<INCOME-CONTINUING>                        (4,992,372)            (10,455,911)
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                 536,179
<CHANGES>                                            0                       0
<NET-INCOME>                               (4,992,372)             (9,919,732)
<EPS-BASIC>                                     (6.93)                 (30.16)
<EPS-DILUTED>                                   (6.93)                 (28.61)


</TABLE>