| 摘要 |
PURPOSE:To obtain a display device having low resistance and low heating quantity by energizing an LED through 3-terminal SCR and a resistor, switching the firing conduction angle of the SCR, thereby simplifying the regulation of the power source voltage, and containing circuit component parts in a mouth piece with interchangeability being provided. CONSTITUTION:LEDs 14-16 are inserted in series through a series circuit of a resistor 12 and a unidirectional 3-terminal SCR13 with an AC power source 11. A series circuit of a conducting angle control circuit 18, a resistor 19 and a capacitor 20 is connected in parallel with the SCR13. Resistors 22, 23 are switched by a switch 21 of the circuit 18 to connect in series with a resistor 24 and a capacitor 25, the connecting point of the resistor 24 and the capacitor 25 is connected to the gate of the SCR13 with a series circuit of a diode 26 and a constant-voltage conductive element 27, and a resistor 28 is connected between the gate and the cathode. A body is contained in a mouth piece 29 which is interchangeable with a bulb, the lever 30 of the switch 21 is sidewisely projected, and the LEDs are sealed in a transparent unit 32 and are integrated with the mouth piece. According to this configuration, even if the power source voltages are different, a display device which can be used by a simple lever operation can be obtained. |
