| 摘要 |
PURPOSE:To make a device small, light and low in its cost by changing over input signals of a video tape recorder and an audio tape recorder electronically with a control signal generated with a built-in mechanical switch of one circuit and one node. CONSTITUTION:When an input cable is not connected to an external mike IN input connecting plug A, a node 4 contacts, a terminal 2 and terminal 3 conduct, a bias current flows through resistances 35 and 22, a transistor 34 is on and a transistor 27 becomes active. A LINE IN input signal inputted from a LINE IN input connecting plug 9 is outputted through the transistor 27 to a signal output terminal 38. When the input cable is connected to an input connecting plug A, the node 4 is released. A bias voltage is applied to a transistor 26 with resistances 24 and 25, the transistor 27 becomes off and for that reason, the transistor becomes active, and an external mike input signal inputted from a node 5 of the input connecting plug A, is outputted through the transistor 26 to the signal output terminal 38. |
