| 摘要 |
PURPOSE:To indicate a level by switched and transferred luminescent colors, by a constitution wherein a plural sets of light-emitting diodes having different luminescent colors are provided, cathodes are connected to a driving circuit, and the feeding to anodes different in luminescent colors are switched 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 transistor (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 arranged, with two of (36a, 36b)- (40a, 40b) in a set, on the back surface of a plastic case C. LEDs in green a and red b are set in a pair. A series circuit of R41 and TR42, which adjusts 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 a power source +B via a switching circuits comprising 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. |
