| 摘要 |
In an electrical comparator, one input (1) of the comparator is connected via a first resistor (3) to the one input of a differential amplifier (4), and the other input (2) of the comparator is connected via a second resistor (2) to the other input of the differential amplifier (4). If the variable input voltage (Ux) exceeds the adjustable threshold voltage (Uw) of the comparator, an auxiliary current (IH), which flows through one (3) of the two resistors, creates a voltage drop which is additively superimposed on the variable input voltage (Ux). Due to this measure, the switch-off voltage of the comparator is lower than its switch-on voltage, the voltage drop across the resistor (3) being equal to the hysteresis of the comparator. The auxiliary circuit contains, apart from the resistor (3) already mentioned, a further resistor (8), a constant voltage generator (7) and a switch (6) controlled by the output of the differential amplifier (4). The magnitude of the hysteresis can be set in a simple manner by appropriately dimensioning the auxiliary circuit. <IMAGE>
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