| 摘要 |
<p>(Case No. 8005) A fail-safe active low-pass filter circuit including a plurality of transistor gates having their inputs coupled to a source of a.c. signals, one of a plurality of field-effect transistor switches coupled to an associated one of the plurality of transistor gates, and a variable R-C network having a variable upper a.c. signal passing level which is determined by which one of the associated transistor gates and field-effect switches is rendered conductive by application of d.c. supply voltage.</p> |
