| 摘要 |
PROBLEM TO BE SOLVED: To display the operation of equipment or the states of functions without wasting power by providing a pilot lamp replacing originally required electric parts in an electric circuit other than a power supply system. SOLUTION: A pilot lamp 2 of an LED is, provided on a volume circuit (electric circuit) 1 for gain control in a preamplifier circuit in place of a resistor as an electric component 3 to be originally provided. The current consumption of the electric component 3 is equal with that of the pilot lamp 2. The electric component 3 is electrified/unelectrified while being interlocked with the ON/OFF of the preamplifier. Even when the electric component 3 is exchanged with the pilot lamp 2, it is necessary not to exert any adverse influence upon the circuit 1 having the electric component 3 and the other electric circuit, especially, upon high frequency characteristics. The pilot lamp 2 is connected matching its polarity in the direction of currents in the circuit. |
