JP4385868B2 - Lighting circuit for switch with display - Google Patents

Description

  The present invention relates to a lighting circuit for a switch with a display, which includes a light emitting diode whose power supply is turned on and off by an operation of a switch inserted between an AC power supply and a load, and displays an energization state to the load.

  Conventionally, as this type of lighting circuit for switch with a display 1 (hereinafter referred to as “lighting circuit”), as shown in FIG. 13, a current transformer 51 in which a primary winding n1 is connected in series to a contact SW. There are provided light-emitting diodes 45 and 46 (hereinafter referred to as “LEDs”) that are turned on by current generated in the next winding n2. In the illustrated example, a series circuit of two LEDs 45 and 46 connected in antiparallel to each other and a resistor R1 is connected between both ends of the secondary winding n2 of the current transformer 51 to constitute the lighting circuit 1 ( For example, see Patent Document 1).

On the other hand, there is also known a lighting circuit 1 that turns on the LED 45 by being directly supplied with electric power from an AC power supply AC through low-voltage indoor wiring. The lighting circuit 1 shown here is obtained by providing a diode D1 in place of the one LED 46 in the lighting circuit 1 described above. For example, as shown in FIG. 14, the lighting circuit 1 is connected in parallel to the contact SW, so that power is supplied when the contact SW is opened to light the LED 45. Further, in the two-wire / three-way wiring type switch 2, as shown in FIG. 15, the lighting circuit 1 is connected between two connection terminals excluding the common terminal, and when the power supply to the load L is cut off. The LED 45 is turned on. In the three-wire switch 2 in which the contact SW is interposed between the AC power supply AC and the load L, as shown in FIG. 16, the lighting circuit 1 is connected in series with the contact SW with respect to the AC power supply AC. The LED 45 is turned on when the SW is closed.
JP-A-8-180768 (page 4, FIG. 9)

  However, the lighting circuit 1 that is directly supplied with power from the AC power source AC is easily affected by a current change that occurs in the low-voltage indoor wiring, and even during periods when the lighting circuit 1 is not supplied with power, for example, noise or load start Inrush current or surge current may flow through the lighting circuit 1, and the LED 45 may be erroneously lit due to these currents. Further, there is a possibility that the LED 45 is erroneously turned on due to a minute current flowing through a stray capacitance generated between a conductor arranged close to the lighting circuit 1.

  The present invention has been made in view of the above reasons, and is capable of lighting a switch with a display so that the display light emitting diode does not light up erroneously even when various currents causing the display light emitting diode to light up erroneously flow. An object is to provide a circuit.

The invention according to claim 1 is a display light emitting diode in which power supply from the AC power supply is turned on and off by operation of a switch inserted between the AC power supply and a load, and noise whose frequency component is higher than that of the AC power supply. This is a capacitor that reduces the impedance to the display light-emitting diode, and the current-flowing path is different from the current-flowing current path for the display light-emitting diode so that the current that causes the display light-emitting diode to light incorrectly does not flow to the display light-emitting diode. The bypass element has a lower impedance to at least one of noise, inrush current, and surge current than the display light emitting diode, and is in series with both the display light emitting diode and the bypass element. resistor is connected Rutotomoni, so that the series circuit of the display light-emitting diode is in parallel with the bypass element Impedance for at least one and connected to the noise and surges and surge current, characterized in that the high protective resistance than the bypass element is added.

  According to this configuration, since the current for erroneously lighting the display light emitting diode is bypassed through the bypass element, the display light emitting diode is not erroneously turned on by the current.

Further, the display light emitting diode may be erroneously turned on due to noise, inrush current, or surge current, and the frequency component of these currents is generally higher than that of the AC power supply. Therefore, in the structure of Claim 1, a capacitive element can be used as a bypass element which becomes a low impedance with respect to these electric currents. That is, it is possible to prevent erroneous lighting of the display light emitting diode by using a capacitor or the like as a bypass element.

Furthermore, according to the above configuration, noise, inrush current, and surge current are less likely to flow through the display light emitting diode by a simple configuration in which a protective resistor is added. As a result, it is possible to prevent the display light emitting diode from being erroneously turned on due to noise, inrush current, or surge current.

According to a second aspect of the present invention, in the first aspect of the present invention, the switch supplies power to the display light emitting diode through a path through which a small current flowing through the stray capacitance generated between the bypass element and the adjacent conductor is supplied to the switch. It is characterized in that it is formed when is shut off.

  Even when the power supply is interrupted by a switch, the display light emitting diode may be erroneously turned on by a minute current flowing through the stray capacitance. Therefore, in the configuration of the fourth aspect, it is possible to prevent erroneous lighting of the display light emitting diode by using a resistor or the like for passing a minute current as a bypass element.

According to a third aspect of the present invention, there is provided the diode according to the first or second aspect , further comprising a diode connected in reverse parallel to the display light emitting diode and having a forward drop voltage smaller than a reverse breakdown voltage of the display light emitting diode. And

  According to this configuration, the current applied to the display light emitting diode in the reverse direction can be made smaller than the reverse breakdown voltage, and as a result, the stress applied to the display light emitting diode can be reduced.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a current reducing resistor connected in series to the display light emitting diode, and a forward voltage drop connected in parallel to a series circuit of the display light emitting diode and the current reducing resistor. Is provided with at least one power supply diode that is equal to or higher than the lighting voltage of the display light emitting diode.

  In this configuration, the voltage applied to the display light emitting diode is determined by the forward drop voltage of the power supply diode, and the display light emitting diode can be lit with substantially the same brightness even for different power supply voltages. .

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, a light-emitting diode that is disposed in the vicinity of the display light-emitting diode and connected in reverse parallel to the display light-emitting diode is added. And

  According to this configuration, by turning on both the display light emitting diode and the light emitting diode, it is possible to display a relatively brighter image than in the case of only the display light emitting diode, and the display is in a visible range. Expansion can be expected. Further, if the light emitting diode has the same specification as that of the display light emitting diode, the power consumption with respect to both polarities of the AC power supply can be made equal to maintain the symmetry of the output waveform of the AC power supply.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a current reducing resistor connected in series to the display light emitting diode and the parallel circuit of the light emitting diode, and both ends of the series circuit of the display light emitting diode and the current reducing resistor. A diode bridge having an AC input terminal connected therebetween, and a diode connected between a DC output terminal of the diode bridge with an anode on the positive electrode side.

  According to this configuration, the display light-emitting diode and the voltage applied to the light-emitting diode are determined by the diode bridge and the forward drop voltage of the diode, and the display light-emitting diode with substantially the same brightness even for different power supply voltages Can be lit. Moreover, since the forward voltage drop of the diode is shared by the display light emitting diode and the light emitting diode, the same function as a total of 6 diodes can be realized by 3 diodes in total with 5 diodes in total.

  Since the present invention bypasses a current that erroneously lights the display light emitting diode by providing the bypass element, there is an advantage that the display light emitting diode is not erroneously turned on by the current.

( Basic configuration )
A switch 2 incorporating the lighting circuit for switch with display 1 (hereinafter referred to as “lighting circuit”) of this configuration example includes a rectangular parallelepiped container 3 as shown in FIG. This switch 2 has a contact SW housed in the body 3 when the handle 4 provided on the front surface of the body 3 (the upper side in the figure is the front) is pushed backward by an operation of a piano handle (not shown). This is a two-wire / three-way wiring compatible type in which the connection state is switched (see FIG. 1). Hereinafter, the configuration of the switch 2 will be described with reference to FIG. 3 which is an exploded perspective view of the switch 2.

  The body 3 is formed by a body 5 having a front opening and a cover 6 having a rear opening coupled to the front side of the body 5. On each side surface of the cover 6 in the left-right direction (lower left in the figure is the left side), it was provided on an attachment frame (not shown) used when attaching the embedded wiring device to a construction surface such as a wall surface. A pair of attachment claws 11 that can be engaged with an instrument attachment hole (not shown) are provided so as to be attached to the attachment frame.

  The internal space of the body 5 is divided into three chambers in the left-right direction by the inner body 12 housed in the body 5, the compartments on both sides serve as terminal housing chambers for accommodating quick connection terminals, and the contact SW is housed in the center. The contact storage chamber is formed. The terminal storage chamber on the right side (upper right in the figure) stores a common terminal plate 13, two locking springs 14 and a release button 15 that constitute a common terminal, and the terminal storage chamber on the left side (lower left in the figure). A first connection terminal including the connection terminal plate 16 and the lock spring 17, a second connection terminal including the connection terminal plate 18 and the lock spring 19, and the release button 20 are housed.

  Each of the connection terminal plates 16 and 18 is integrally formed with a contact holding piece 22 disposed in the contact storage chamber (a contact holding piece integral with the contact terminal plate 16 is not shown). A fixed contact 23 is provided at each of the distal ends of the two. Both contact holding pieces 22 are formed in a shape in which the fixed contacts 23 face each other in the left-right direction. Between the two fixed contacts 23, an opening / closing element 24 provided with a movable contact 27 that constitutes a contact SW together with the fixed contact 23 is disposed at a portion facing each fixed contact 23. The movable contact 27 is integrally formed on the front surface side and the back surface side of the switch 24. The switch 24 is movable between a position where the fixed contact 23 and the movable contact 27 are brought into contact with each other and a position where the other fixed contact 23 and the movable contact 27 are brought into contact with each other. Stored in contact. In this state, the switch 24 is electrically connected to the common terminal board 13.

  On the other hand, there is a reversing mechanism that alternately moves the opening / closing element 24 in the opposite direction every time the handle 4 is pushed backward, and the reversing mechanism is exposed to the front side of the cover 6 through the through hole 33 of the cover 6. An oscillating element 31 that is slidably attached to the cover 6 in the state is provided. The oscillator 31 is connected to the opening / closing element 24 via a reversing spring 29 formed of a compression coil spring. When the oscillator 31 swings, the reversing spring 29 is compressed most in the middle of the swinging range. Go through position. Before and after this position, the direction of the spring force acting on the switch 24 from the reversing spring 29 is reversed, and the switch 24 is rapidly moved by the spring force of the reversing spring 29 to switch the contact SW. Here, the oscillator 31 is stable in a state in which one end portion in the left-right direction is inclined forward and either left or right.

  The handle 4 is spring-biased forward by a return spring 40 provided between the handle 6 and a slide cam 38 constituting a reversing mechanism is slidable along the rear surface of the handle 4 on the rear surface side of the handle 4. It is arranged. When the handle 4 is pushed rearward against the return spring 40, the slide cam 38 swings the rocker 31 backward by pushing one end of the rocker 31 closer to the front. It is something to lean on. As a result, the switch 24 is moved and the contact SW is switched.

In short, the switch 2 of this configuration example is in a state in which the common terminal plate 13 and the connection terminal plate 16 are conductive each time the handle 4 is pushed backward by the above-described configuration (that is, the common terminal and the first connection terminal are conductive). And a state where the common terminal plate 13 and the connection terminal plate 18 are conductive (that is, a state where the common terminal and the second connection terminal are conductive).

In this configuration example , two switches 2 corresponding to the three-way wiring are used to connect the connection terminal plates 16 (first connection terminals) of both the switches 2 as shown in FIG. Are connected to each other, and a series circuit of an AC power supply AC and a load L is connected between the common terminal plates 13 (common terminals) of both switches 2, whereby an AC power supply AC is provided. The power supply to the load L can be turned on / off by either of the two switches 2. However, it is assumed here that the switch 2 is used with low-voltage indoor wiring (usually 100V, 200V in Japan).

  Incidentally, as shown in FIG. 3, a display substrate 42 in which a lighting circuit 1 for displaying a state of power supply to the load L by blinking of a light emitting diode (hereinafter referred to as “LED”) is formed in the container 3. It is stored. The display substrate 42 is mounted on the front side of the inner body 12, and the input terminals 43 and 44 are electrically connected to the connection terminal plates 16 and 18. The lighting circuit 1 has an LED blinking according to the connection state of the contact SW with a circuit configuration to be described later, and two LEDs 45 and 46 are arranged with the light emitting surface facing forward. A display window 47 is provided in a portion corresponding to the front of the LEDs 45 and 46 on the side of the recess 32 on the front surface of the cover 6. A translucent LED cover 48 is fitted into the display window 47, and light from both the LEDs 45 and 46 is emitted forward through the LED cover 48.

  In the lighting circuit 1, both the LEDs 45 and 46 are turned on by energizing the input terminals 43 and 44. As shown in FIG. 1, both connection terminal plates 16 and 18 (first and second connection terminals). By being connected in between, both the LEDs 45 and 46 are turned off in a state where power is supplied to the load L, and both the LEDs 45 and 46 are turned on in a state where power is not supplied to the load L. That is, the on / off state of the power supply from the AC power supply AC to the load L is displayed by the blinking of the LEDs 45 and 46 viewed from the display window 47.

As shown in FIG. 4, the lighting circuit 1 includes two LEDs 45 and 46 connected in antiparallel to each other between the input terminals 43 and 44. A resistor R1 is inserted between the input terminals 43 and 44 in series with the parallel circuit of the LEDs 45 and 46 to prevent the LEDs 45 and 46 from being damaged by a large current flowing through the LEDs 45 and 46. In this configuration example , a resistor R1 having a resistance value of 500 kΩ is used. Here, one LED 45 is an LED 45 provided as a light emitting diode for display, and the other LED 46 may be of another specification with the LED 45. However, in this configuration example , both the LEDs 45 and 46 have the same specification. This maintains the symmetry of the output waveform of the AC power supply AC by making the power consumption in the lighting circuit 1 equal for both polarities of the AC power supply AC. In addition, a diode can be connected instead of one LED 46 as in the conventional configuration, but by using two LEDs 45 and 46 as in this configuration example , a relatively bright display can be achieved. In addition, since the two LEDs 45 and 46 are arranged close to each other as described above, the viewing angle of the LEDs 45 and 46 is wider than that of the single LED 45 and 46. In a state where the provided switch 2 is attached to a wall surface or the like, it can be expected that the range in which the LEDs 45 and 46 can be visually confirmed is enlarged.

By the way, in this configuration example , the lighting circuit 1 includes a bypass element connected in parallel to the LEDs 45 and 46 as shown in FIG. In the present configuration example , the bypass element is a capacitor C1 that has low impedance against noise whose frequency component is higher than that of the AC power supply AC. Therefore, between the input terminals 43 and 44 of the lighting circuit 1, noise flows through the capacitor C1 having a low impedance to noise. In short, in the present configuration example , by providing the capacitor C1 through which noise passes through the LED 45, 46, the noise is bypassed without passing through the LED 45, 46.

  Furthermore, by providing the capacitor C1 as a bypass element, not only noise but also inrush current or surge current whose frequency component is higher than that of the AC power supply AC can be bypassed without passing through the LEDs 45 and 46. However, the bypass element is selected according to the current to be bypassed, and is not limited to the capacitor C1 as described above. For example, an element whose impedance changes according to the voltage at both ends, such as a surge absorber, may be used. .

  As described above, it is possible to prevent erroneous lighting of the LEDs 45 and 46 by flowing a current for erroneously lighting the LEDs 45 and 46 such as noise, inrush current, and surge current through a different path from the LEDs 45 and 46. Moreover, even when the lighting circuit 1 is supplied with power from the AC power supply AC and lights the LEDs 45 and 46, noise, inrush current and surge current are bypassed without passing through the LEDs 45 and 46, so that the LEDs 45 and 46 are turned on. It is also possible to prevent the brightness of the LEDs 45 and 46 from changing and the lighting of the LEDs 45 and 46 to become unstable, or the LED 45 and 46 to fail due to an overcurrent flowing through the LEDs 45 and 46.

  Further, as shown in FIG. 5, even when the diode D1 is connected instead of the LED 46 connected in antiparallel to the LED 45 as the display light emitting diode, the erroneous lighting of the LED 45 is caused by the capacitor C1 in the same manner as described above. Can be prevented. FIG. 6 shows the difference in the voltage across the LED 45 depending on the presence or absence of the capacitor C1 when an AC voltage is applied to the input terminals 43 and 44 in the configuration of FIG. As described above, even when the LED 45 is turned on, when the capacitor C1 of FIG. 6B is provided, noise flowing to the LED 45 is reduced as compared with the case where the capacitor C1 of FIG. 6A is not provided. .

  Note that the lighting circuit 1 described above is not limited to the two-wire / three-way wiring compatible switch 2, but is connected to the contact SW in parallel in, for example, a two-wire single-sided switch, thereby opening the contact SW. Sometimes the LEDs 45 and 46 are turned on, or the contact SW is connected in series to the AC power supply AC in a three-wire switch in which the contact SW is interposed between the AC power supply AC and the load L. The LEDs 45 and 46 may be turned on at the time of closing (see FIGS. 14 and 16).

( Embodiment 1 )
As shown in FIG. 7, the lighting circuit 1 of the present embodiment is different from the lighting circuit 1 of the basic configuration in that it includes a protective resistor R2 connected in series to a series circuit of an LED 45 and a resistor R1. Here, the protective resistor R2 is inserted in series with the LED 45 between both ends of the capacitor C1, so that the series circuit of the LED 45 and the protective resistor R2 is connected in parallel to the capacitor C1 as a bypass element. . In the present embodiment, a diode D1 is provided instead of the LED 46 connected in reverse parallel to the LED 45 as a display light emitting diode in the basic configuration .

  As the protective resistor R2, a resistor having a higher impedance to noise than that of the capacitor C1 is selected. However, a resistor having a resistance value of 10Ω is used here so that the LED 45 is not darkened by providing the protective resistor R2. Thus, when noise is generated between the input terminals 43 and 44 of the lighting circuit 1, the noise is prevented from flowing through the series circuit of the protection resistor R <b> 2 and the LED 45. Even when the bypass element is intended for inrush current and surge current instead of noise, it is possible to prevent the inrush current and surge current from flowing to the LED 45 by providing the protective resistor R2.

  Regarding the resistor R1 connected in series with the LED 45 and the capacitor C1, a resistor having a high impedance of 1 MΩ, for example, may be used instead of the resistor having a resistance value of 500 kΩ. As a result, when an appliance having a relatively low start-up voltage such as an inverter lighting fixture or a lighting fixture with a sensor function is used as the load L, the load L malfunctions due to a leakage current flowing through the lighting circuit 1 to the load L. Can be prevented. However, if the resistance value of the resistor R1 is changed from 500 kΩ to 1 MΩ, it is desirable to change the LED 45 to a high luminance type having twice the luminance. That is, the luminance of the LED 45 is changed in inverse proportion to the magnitude of the leakage current flowing through the lighting circuit 1. As a result, it is possible to prevent the LED 45 from becoming dark while reducing the leakage current flowing to the load L through the lighting circuit 1.

For the diode D1 connected in antiparallel to the LED 45, a diode having a relatively low forward voltage drop (about 0.2V) such as a Schottky diode is used. Since the forward voltage drop of the diode D1 is applied in the reverse direction with respect to the LED 45, the rush current in the forward direction of the diode D1 is obtained by using the diode D1 having a relatively small forward voltage drop. Even when a large current such as a surge current flows, it is possible to prevent a large voltage from being applied to the LED 45 in the reverse direction. Further, even when the lighting circuit 1 is supplied with power from the AC power supply AC and the LED 45 is lit, if the forward voltage drop of the diode D1 is set smaller than the reverse breakdown voltage of the LED 45, the stress applied to the LED 45 is reduced. This can be reduced, and the effect of extending the life of the LED 45 can be expected. Other configurations and functions are the same as the basic configuration .

( Embodiment 2 )
In the lighting circuit 1, a minute current may flow through stray capacitance generated between the lighting circuit 1 and a conductor adjacent to the lighting circuit 1. The conductor close to the lighting circuit 1 here is, for example, an electric wire grounded together with one end of the AC power supply AC, and forms a closed circuit together with the lighting circuit 1 by generating a stray capacitance with the lighting circuit 1. Is. As shown by broken lines in FIGS. 15 and 16, when such an electric wire 49 is close to the electric wire 50 connected to the lighting circuit 1, for example, between the electric wires 49 and 50. A stray capacitance C2 may occur. The LEDs 45 and 46 may be erroneously turned on not only by noise, surge current and inrush current but also by a minute current flowing through the stray capacitance C2.

The lighting circuit 1 of the present embodiment bypasses a minute current flowing through the stray capacitance C2 by a bypass element, and is connected in parallel to the LED 45 in the lighting circuit 1 of the first embodiment as shown in FIG. A resistor R3 is added as a bypass element.

Since the forward drop voltage of the LED 45 is applied to the resistor R3, when the forward drop voltage of the LED 45 is 1.7 V, a resistance value is set so that a minute current of up to 0.5 mA flows through the resistor. Is 3.4 kΩ. According to this configuration, even if a minute current flows to the lighting circuit 1 through the stray capacitance generated between the lighting circuit 1 and a conductor adjacent to the lighting circuit 1, the minute current flows through the resistor R3. It can prevent lighting. Other configurations and functions are the same as those of the first embodiment .

( Embodiment 3 )
As shown in FIG. 9, the lighting circuit 1 of the present embodiment is obtained by providing a capacitor C3 as a bypass element in place of the resistor R3 in the lighting circuit 1 of the second embodiment .

Since the forward drop voltage of the LED 45 is applied to the capacitor C3, when the forward drop voltage of the LED 45 is 1.7V, the capacitance is such that a minute current of up to 0.5 mA flows to the capacitor C3. For example, 5 μF is used. According to this configuration, even if a minute current flows to the lighting circuit 1 through the stray capacitance generated between the conductor adjacent to the lighting circuit 1, the minute current flows through the capacitor C3. It is possible to prevent erroneous lighting. In addition, since the capacitor C3 is adopted as the bypass element, the bypass element has low impedance with respect to the high-frequency inrush current and surge current, and can prevent the high-frequency inrush current and surge current from flowing into the LED 45. It can protect against current and surge current. Other configurations and functions are the same as those of the second embodiment .

( Embodiment 4 )
As shown in FIG. 10, the lighting circuit 1 of the present embodiment is for three power supplies connected in parallel to the series circuit of the LED 45 and the protective resistor R2 with respect to the lighting circuit 1 of the first embodiment . Diodes D2 to D4 as diodes are added. Further, the diode D1 connected in antiparallel to the LED 45 is omitted, and a diode D5 connected in antiparallel to the series circuit of the diodes D2 to D4 is added. In this configuration, the protective resistor R2 functions as a current reducing resistor. The three diodes D2 to D4 are connected in series in the same direction as the LED 45 between the input terminals 43 and 44. However, the capacitor C1 as a bypass element is omitted in FIG.

In the present embodiment, the sum of forward drop voltages of the diodes D2 to D4 (hereinafter referred to as “sum voltage”) is applied to the series circuit of the LED 45 and the protective resistor R2. When all of the diodes D2 to D4 have a forward drop voltage of 0.7V, the sum voltage is 2.1V, and this sum voltage is applied to the series circuit of the LED 45 and the protection resistor R2. become. Even if a different voltage is applied between the input terminals 43 and 44, the change of the sum voltage is small. Therefore, even if a different voltage is applied between the input terminals 43 and 44, the LED 45 can be lit with substantially the same brightness. Therefore, this lighting circuit 1 can be used for both AC power supply AC of 100V and 200V, for example. Other configurations and functions are the same as those of the first embodiment .

( Embodiment 5 )
As shown in FIG. 11, the lighting circuit 1 of the present embodiment has an LED 46 added in antiparallel to the LED 45 with respect to the lighting circuit 1 of the fourth embodiment , and the diode D5 is used for power supply together with the two diodes D6 and D7. A series circuit is configured as a diode. That is, the diodes D2 to D4 as power supply diodes corresponding to the LED 45 are connected between the input terminals 43 and 44 in the same direction as the one LDE 45, and the LED 46 is connected in the same direction as the other LED 46. Diodes D5 to D7 are provided as corresponding power supply diodes.

  Therefore, in this embodiment, the sum voltage generated between both ends of the diodes D2 to D4 and D5 to D7 corresponding to the LEDs 45 and 46 in both directions between the input terminals 43 and 44 is the LED 45 and 46 and the protective resistor. It is applied to the series circuit of R2.

In addition, as shown in FIG. 12, a circuit that operates in the same manner as in the present embodiment uses a diode bridge DB including four diodes and a single diode D8 instead of the six diodes D2 to D7. Can be configured. Here, the AC input terminal of the diode bridge DB is connected between both ends of the series circuit of the LEDs 45 and 46 and the protective resistor R2, and the diode D8 is connected between the DC output terminals of the diode bridge DB. The diode D8 has an anode connected to the positive electrode side of the DC output terminal. Other configurations and functions are the same as those of the fourth embodiment .

It is a wiring diagram which shows the structure using the switch of the basic composition of this invention. It is a perspective view which shows a switch same as the above. It is a disassembled perspective view which shows the structure of a switch same as the above. It is a circuit diagram which shows a lighting circuit same as the above. It is a circuit diagram which shows the other structure of the lighting circuit same as the above. (A) is explanatory drawing which shows the both-ends voltage of LED when not providing a capacitor | condenser, (b) is explanatory drawing which shows the both-ends voltage of LED when a capacitor | condenser is provided. It is a circuit diagram which shows the lighting circuit of Embodiment 1 of this invention. It is a circuit diagram which shows the lighting circuit of Embodiment 2 of this invention. It is a circuit diagram which shows the lighting circuit of Embodiment 3 of this invention. It is a circuit diagram which shows the lighting circuit of Embodiment 4 of this invention. It is a circuit diagram which shows the lighting circuit of Embodiment 5 of this invention. It is a circuit diagram which shows the other circuit structure same as the above. It is a circuit diagram which shows a prior art example. It is a wiring diagram which shows the structure using a prior art example. It is a wiring diagram which shows the other structure using a prior art example. It is a wiring diagram which shows other structure using a prior art example.

Explanation of symbols

1 (for switch with display) lighting circuit 2 switch 45 (for display) light emitting diode 46 light emitting diode AC AC power supply C1, C3 capacitor (bypass element)
D1, D8 Diode D2-D4 (For power supply) Diode DB Diode bridge L Load R2 Protection resistance R3 Resistance (Bypass element)

Claims (6)

A light emitting diode for display in which the power supply from the AC power supply is turned on and off by the operation of a switch inserted between the AC power supply and the load, and a capacitor having a lower impedance to noise whose frequency component is higher than that of the AC power supply. There, a may provide a current path for the lighting in the display light-emitting diode path of current for lighting incorrectly display light-emitting diodes flows the current to not flow to the display light-emitting diode and a bypass element to form a different route provided, the bypass device, the noise and surges and the impedance of the at least one surge current is lower than the display light-emitting diode, resistor in series is connected to both the display light-emitting diode and a bypass element Rutotomoni, The series circuit with the light emitting diode for display is connected in parallel with the bypass element, and noise and Input current and surge currents and the at least one display with switch lighting circuit characterized in that the impedance is added a high protective resistance than the bypass element against. The bypass element forms a path for passing a minute current flowing through a stray capacitance generated between adjacent conductors when the switch cuts off power supply to the display light emitting diode. The lighting circuit for a switch with a display according to claim 1. The switch lighting circuit with a display according to claim 1 or 2 , further comprising a diode connected in reverse parallel to the display light emitting diode and having a forward voltage drop smaller than a reverse breakdown voltage of the display light emitting diode. . A current reducing resistor connected in series to the display light emitting diode, and at least one current connected in parallel to a series circuit of the display light emitting diode and the current reducing resistor, the forward voltage drop being equal to or higher than the lighting voltage of the display light emitting diode 4. A lighting circuit for a switch with a display according to claim 3, further comprising the above power supply diode . With display switch lighting circuit according to claim 1 or claim 2, characterized in that light-emitting diodes connected in antiparallel to the disposed proximate to the display light-emitting diode display light-emitting diodes are added . A current reducing diode connected in series to the display light emitting diode and a parallel circuit of the light emitting diode, a diode bridge having an AC input terminal connected between both ends of the series circuit of the display light emitting diode and the current reducing resistor, and a diode lighting circuits for display with switch according to claim 5, characterized in that the anode bridge DC output terminal and a diode connected in the positive electrode side.

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