GB2146181A

GB2146181A - Lighting control device

Info

Publication number: GB2146181A
Application number: GB08323340A
Authority: GB
Inventors: Yong Ji Lee
Original assignee: WOOIL JEONKWANG CO Ltd
Current assignee: WOOIL JEONKWANG CO Ltd
Priority date: 1983-08-31
Filing date: 1983-08-31
Publication date: 1985-04-11
Also published as: GB8323340D0

Abstract

A lighting control device is incorporated in an electric bulb socket (Fig. 2) and uses a rotary switch 2 to connect a mains terminal 10 to the bulb via a direct link, a diode 6 or a triac-diac circuit 4, 5 R, C2 to provide different levels of illumination. <IMAGE>

Description

SPECIFICATION Lighting control device The present invention relates to a lighting control device usable to control the level of illumiriation produced by a conventional electric incandescent lamp or bulb.

Known lighting control devices or dimmer switches employ a variable resistor or selected resistors to adjust the power supplied to a bulb. The use of resistors naturally results in power loss, generates heat and involves a bulky device. Other arrangements have employed a special bulb with several incandescent filaments with different illumination powers. Such bulbs are however costly.

There is thus a need for an improved lighting control device.

According to the present invention there is provided a lighting control device comprising a pair of terminals for connectipn to an electric a.c. power source and a selector switch connectible to one of said terminals via one of a plurality of selective connections, an incandescent light source being connectible between the switch and the other of said terminals; wherein the selective connections at least include a direct connection, a series diode and a circuit including a triac and diac providing respectively a higher, intermediate and a lower level of illumination from the source.

The device can form an exceptionally compact package and can be built into a conventional type of light bulb socket. Thus in another aspect the invention provides a lighting control device for incorporation in the socket of a light bulb to control the level of illumination therefrom, said device comprising a switch accessible from the exterior of the socket which serves selectively to connect the bulb to an a.c. power source during use through different circuit connections, one of which comprises a direct connection and others of which incorporte semi-conductor devices.

The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, wherein: Figure 1 is a schematic circuit diagram depicting a device constructed in accordance with the invention; and Figure 2 is a perspective view of a light socket embodying the device of Fig. 1.

As shown in Fig. 1, a lighting control device comprises terminals 10, 11 which are intended to be connected to an electric a.c.

mains supply and terminals 12, 1 3 which are intended to be connected to a light source Lp in the form of an incandescent light bulb 1. A selector switch 2 has a common terminal or wiper 7 connected to the terminal 1 2 and the three selection terminals 3, 3', 3". A capacitor Ct is connected across the terminals 10, 11 and an inductor L is connected in series with a triac 4 between terminals 3 and 10. A resistor R and a capacitor C2 are connected in series across the triac 4. A diac 5 is connected between the control electrode of the triac 4 and the junction between the resistor R and the capacitor C2. A diode 6 is connected between the terminal 3' and the inductor L and the terminal 3" is connected directly to the inductor L. The inductor L and the capacitor C, serve as a smoothing network.

The switch 2 can select one of three alternative circuit connections to energize the light bulb 1. The highest level of illumination occurs when the switch 2 selects the terminal 3" with the direct connection to the terminal 10. The next highest level of illumination occurs when the switch 2 selects the terminal 3' so that the diode 6 provides half-wave rectified power to the bulb 1. The lowest level of illumination occurs when the switch 2 selects the terminal 3. In this case the triac 4 is triggered into conduction by the diac 5 in dependence on the time constant C2R.

Fig. 2 shows how the compact control device can be assembled into a light bulb socket.

1. A lighting control device comprising a pair of terminals for connection to an electric a.c. power source and a selector switch connectible to one of said terminals via one of a plurality of selective connections, an incandescent light source being connectible between the switch and the other of said terminals; wherein the selective connections at least in dude a direct connection, a series diode and a circuit including a traic and diac providing respectively a higher, intermediate and a lower level of illumination from the source.

2. A control device according to claim 1, wherein the switch is a manually-operable rotary selector switch.

3. A control device according to claim 1 or 2, wherein a capacitor is connected between said terminals and an inductor is conected to said one terminal and is incorporated in each of said selective connections.

4. A control device according to any one of claims 1 to 3, wherein the circuit is composed of the traic in series between the switch and the one terminal, a resistor and a capacitor connected in series across the triac and the diac is connected between the control electrode of the triac and the junction between the resistor and the capacitor.

5. A lighting control device for incorporation in the socket of a light bulb to control the level of illumination therefrom, said device

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Lighting control device The present invention relates to a lighting control device usable to control the level of illumiriation produced by a conventional electric incandescent lamp or bulb. Known lighting control devices or dimmer switches employ a variable resistor or selected resistors to adjust the power supplied to a bulb. The use of resistors naturally results in power loss, generates heat and involves a bulky device. Other arrangements have employed a special bulb with several incandescent filaments with different illumination powers. Such bulbs are however costly. There is thus a need for an improved lighting control device. According to the present invention there is provided a lighting control device comprising a pair of terminals for connectipn to an electric a.c. power source and a selector switch connectible to one of said terminals via one of a plurality of selective connections, an incandescent light source being connectible between the switch and the other of said terminals; wherein the selective connections at least include a direct connection, a series diode and a circuit including a triac and diac providing respectively a higher, intermediate and a lower level of illumination from the source. The device can form an exceptionally compact package and can be built into a conventional type of light bulb socket. Thus in another aspect the invention provides a lighting control device for incorporation in the socket of a light bulb to control the level of illumination therefrom, said device comprising a switch accessible from the exterior of the socket which serves selectively to connect the bulb to an a.c. power source during use through different circuit connections, one of which comprises a direct connection and others of which incorporte semi-conductor devices. The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, wherein: Figure 1 is a schematic circuit diagram depicting a device constructed in accordance with the invention; and Figure 2 is a perspective view of a light socket embodying the device of Fig. 1. As shown in Fig. 1, a lighting control device comprises terminals 10, 11 which are intended to be connected to an electric a.c. mains supply and terminals 12, 1 3 which are intended to be connected to a light source Lp in the form of an incandescent light bulb 1. A selector switch 2 has a common terminal or wiper 7 connected to the terminal 1 2 and the three selection terminals 3, 3', 3". A capacitor Ct is connected across the terminals 10, 11 and an inductor L is connected in series with a triac 4 between terminals 3 and 10. A resistor R and a capacitor C2 are connected in series across the triac 4. A diac 5 is connected between the control electrode of the triac 4 and the junction between the resistor R and the capacitor C2. A diode 6 is connected between the terminal 3' and the inductor L and the terminal 3" is connected directly to the inductor L. The inductor L and the capacitor C, serve as a smoothing network. The switch 2 can select one of three alternative circuit connections to energize the light bulb 1. The highest level of illumination occurs when the switch 2 selects the terminal 3" with the direct connection to the terminal 10. The next highest level of illumination occurs when the switch 2 selects the terminal 3' so that the diode 6 provides half-wave rectified power to the bulb 1. The lowest level of illumination occurs when the switch 2 selects the terminal 3. In this case the triac 4 is triggered into conduction by the diac 5 in dependence on the time constant C2R. Fig. 2 shows how the compact control device can be assembled into a light bulb socket. CLAIMS

5. A lighting control device for incorporation in the socket of a light bulb to control the level of illumination therefrom, said device comprising a switch accessible from the exterior of the socket which serves selectively to connect the bulb to an a.c. power source during use through different circuit connections, one of which comprises a direct connection and others of which incorporate semiconductor devices.

6. A device substantially as described with reference to, and as illustrated in, Fig. 1 of the accompanying drawing.

7. An electric light bulb socket incorporating or embodying a device according to any one of the preceding claims.

8. An electric light bulb socket substantially as described with reference to, and as illustrted in Fig. 2 or Figs. 1 and 2 of the accompanying drawing.