| 摘要 |
PURPOSE:To attain a fail-safe circuit from which no oscillation output is generated when an input signal is not higher than a power voltage by setting a gate voltage of a PUT of an oscillation circuit at least to the power voltage, clamping the input signal to the gate voltage of the PUT. CONSTITUTION:After the PUT 12 is turned on by an input signal e1 to be oscillated in an oscillation circuit 12, the PUT 12 is kept in the conductive state until an anode current Ia [Ia Vs/(11+R12)] flowing to the PUT 12 is larger than a gate current Ig [Ig Vs.(R14+R15)R14.R15] and the anode voltage is nearly zero. Thus, a high level oscillation pulse is generated only when the input signal level rises to an 'H' level, and the put 12 keeps conduction until the input signal reaches an 'L' level further so as to prevent the repetitive generation of the high level oscillation pulse.
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