| 摘要 |
PURPOSE:To indicate a level by switched and transferred luminescent colors, by providing a plurality of packages of light-emitting diodes different in luminescent colors, by connecting cathodes to a driving circuit, and by switching the feeding to anodes having different luminescent colors by a detection level output. CONSTITUTION:A signal at a connecting point between a power amplifier 1 and a speaker 2 is given to resistors (R) 7-11 and transistors (TR) 12-16, both of which are provided for setting an indication level. An LED22 is lighted normally, indicating a zero point. LEDs 36-40 are packaged with two elements of (36a, 36b)-(40a, 40b) in a pair and with LEDs in green (a) and red (b) in a couple. A series circuit of R41 and TR42 adjusting the drive gain of LEDs 36-40 is connected to the common terminal side of Rs 7-11. Anodes on the sides a and b of LEDs 36-40 are connected to a power source +B via a switching circuit constituted by TRs 45, 46 and 47, 48. By this constitution, an output of a level detection circuit can be indicated by switched and transferred luminescent colors. |
