| 摘要 |
<p>In a protective relay timing circuit including a timing capacitor which is charged by a signal supplied to an input terminal, there is provided a junction-field effect transistor connected in a source-follower arrangement and coupled to the timing capacitor such that the voltage on the source electrode of the transistor is indicative of the voltage appearing on the timing capacitor. Circuitry is also provided to monitor the voltage on the source electrode and to render the gate-to-source junction of the transistor conductive in response to the voltage on the source electrode attaining a preselected level, whereupon the capacitor discharges through said junction.</p> |
