Night Lamps

8/13/2019 Night Lamps

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Night Lamps

Ashok K. DoctorHere are two night lamp circuits using LEDs. One could be used as a night-vision clock and

the other as a T lamp. !oth the circuits are A" operated and consume ver# little power.

These are also protected against mains $luctuations. The night-vision lamp uses twelve LEDsarranged in the circular pattern o$ a wall clock% while the T lamp uses &' LEDs in prism

$ormat.

Fig. 1: Night-vision clock circuit

(ig.) shows the circuit o$ night-vision clock. "apacitor ") *+.&&,( reduces the current to

sa$e limit% diode D) provides recti$ied D" to bring out the characteristic colour o$ white LEDs

and the ) /ener diode maintains the voltage at a sa$e level. 0esistor 0& protects thecircuit against high inrush current% while resistor 0) is used $or additional protection o$ the

LEDs.

Fig. 2: leds mounted through drilled holes Fig. 3: leds mounted below the band


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Assemble the circuit on a general-purpose 1"! and mount the white LEDs *LED) through

LED)&% through drilled holes% in the circular $ormat o$ the clock dial as shown in (ig. &.2imilarl#% #ou can mount LEDs on another dial o$ the clock as shown in (ig. 3.

(ig. ' shows the T lamp circuit. 4atching T in darkness puts strain on #our e#es. 2o an

illumination o$ )+-)4 is recommended. The circuit described here is known as Ken 2chult/circuit. 5t uses a total o$ &' white LEDs *LED)3 to LED36 and is well balanced againstsurges and voltage spikes. The lamp produces almost no heat.

Fig. 4: tv lamp circuit

Assemble the circuit on a general-purpose 1"!% with the white LEDs *LED)3 through LED36

mounted in a triangular $ormat *(ig. . 7ow enclose it in the proposed T lamp $ittingshown in (ig. 6.

Fig. 5: leds mounted in a triangular ormaton a general-purpose p!b


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Fig. ": tv lamp ittings


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Night Lamp From Scrap CFL

85L57D 8. 29TA0% :EEA7 2. ;HODAKE A7D 10O(. 1.!.:O2H5

Compact fluorescent lamps (CFLs) are available in different shapes and power ratings. Theseconsist of an electronic ballast circuit and a programmable-logic-controlled tubelight. Most CFL

manufacturers offer a guarantee of half a year on their product.

5n an unserviceable "(L% the $ilament has reached the end o$ its li$e but there is ever#possibilit# that the electronic ballast circuit inside the bottom o$ the "(L is in working

condition. The night lamp circuit described here uses the serviceable electronic circuit $itted

in the base o$ an ))-watt "(L.

Fig. 1: An efficient night lamp circuit

(or constructing this night lamp% remove the "(L glass tube and replace it with $our white

LEDs as described below.


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Fig. 2: LEDs arrangement in waste CFL

9se the components $rom the ballast circuit and a series combination o$ $our bright whiteLEDs as shown in (ig. ). 0emove all other components $rom the original ballast circuit. As

per the re=uirement o$ light intensit# in #our room% #ou can increase the number o$ white

LEDs up to eight.

As shown in (ig. )% the $ull-wave bridge recti$ier comprising diodes D) through D' converts

A" voltage into D" voltage. 2nubber capacitor ") at the input reduces the line input voltageo$ &3+ to a ver# low-level A" voltage. 2eries current-limiting resistor 0& and series

inductor coil L) avoid voltage spikes.

(it the circular 1"! in the waste "(L holder and #our night lamp is read# $or use.


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Night Lamps