| 摘要 |
<p>The E.C. cell (1) has a rear electrode (2) electrically connected with the plus input of one comparator (3), and the minus input of a second comparator. The negative input of the first comparator (3) is connected via the wiper of a variable resistor (5) to a terminal (7) which has an applied voltage (+UB). The plus input of the second comparator (4), is connected similarly to a terminal (8) with an applied negative voltage (-UB). The collectors of two switching transistors (9,10) are also connected to the rear electrode (2) of the cell (1), with their emitters supplied by the two voltage terminals (+UB1-UB). The comparator inputs are connected to the output (SA,SB) of a central control unit (12) which may be a microprocessor. The base connections of the transistors are connected to a second output (A,B) of the control unit (12). To control the cell (1), a number of current impulses of opposing polarity is used to write in a display or cancel it.</p> |
