| 摘要 |
PURPOSE:To widen the selection width of a time constant by connecting a time constant to the base of a transistor via FET. CONSTITUTION:Alternating current 1 is rectified with respect to full waves by full- wave rectifier 2 and led to electronic switching device P, and then capacitor 9 is charged via resistance 4, transistor 3 and FET8. As the charging voltage rises, the negative gatesource potential of FET8 increases and the conduction resistance of FET8 increases. As a result, the base current of transistor 3 decreases and its conduction resistance increases, and consequently the across potential of voltage divider 5 rises, so that capacitor 9 is suddenly charged via resistance 6. Therefore, FET8 and transistor 3 both turn off and the current of load 11 is ceased. |
