| 摘要 |
PURPOSE:To save energy while preventing a signal in switching from leaking by controlling a semiconductor element, connected in the opposite direction, by a switching control power source by using this semiconductor element to change over a TV receiver with VTR as an additional device. CONSTITUTION:A TV signal from antenna terminal 4a of antenna 4 and a picture signal from converter terminal 3a of VTR device 2 are changed over by high- frequency switch 5 and supplied to TV1. This switch 5 is composed of reversely connected diodes 16 and 17 connected to terminal 4a and diodes 18 and 19 connected in series to terminal 3a, and the connection points of diodes 16 and 17, and 18 and 19 are connected to switching control power terminal 20 via resistances 24 and 25 respectively. When terminal 20 is opened or short-circuited, diodes 16-19 are turned on and an input to terminal 4a is applied to antenna input terminal 1a to hold TV reception in readiness; when a positive voltage is applied to terminal 20, diodes 16-19 are turned off and a signal to terminal 3a is applied to terminal 1 without leakage and reproduced. |
