| 摘要 |
<p>PURPOSE:To suppress the heat generation by connecting each step-down resistive means in series with two pairs of luminous bodies and reducing the electric current which flows in a circuit for detecting breakage to the min. by detecting the breakage state of each luminous body on the basis of the potential difference at both the edges of the step-down resistive means. CONSTITUTION:An illumination circuit for a headlight controls the ON/OFF of the headlight according to the ON/OFF state of the contact points between a lighting switch LTS assembled in a combination switch CMB, passing switch PSG, and a high/low selecting switch HLS, and the circuits 1 and 2 for detecting the breakage of a high beam side filament are installed in a circuit for controlling the extinction lighting of the high beams LH1 and RH2 of the headlight in a twilight state. As for each breakage detecting circuit 1, 2, the conduction of a transistor Tr8 is controlled according to the potential difference between at both the edges of the step-down resistors RR1 and RR2 which are connected in series with the respective high beam side filaments, in series connection, and when the conduction of of the transistor Tr8 is cut off because of the generation of breakage, a warning lamp WPL is put ON.</p> |
