There are already published diagrams for automatic emergency lights but this fully automatic led base emergency light has the following special advantages.
1. Fully automatic - The name suggests its character. The emergency light charging is fully controlled and you don't have to worry about over charging of battery.
2. The emergency night light - This circuit is designed to glow leds where there no light in the room and only when there is no mains supply available. If one of them are available, the leds will not glow and the power is saved. This is achieved by using LDR and a PNP transistor.So we can plug the emergency lamp on the mains socket overnight without the fear of overcharging or waste of energy.
The working of this design is very simple by the way we can divide this emergency light circuit into two sections.
1. Fully automatic - The name suggests its character. The emergency light charging is fully controlled and you don't have to worry about over charging of battery.
2. The emergency night light - This circuit is designed to glow leds where there no light in the room and only when there is no mains supply available. If one of them are available, the leds will not glow and the power is saved. This is achieved by using LDR and a PNP transistor.So we can plug the emergency lamp on the mains socket overnight without the fear of overcharging or waste of energy.
The working of this design is very simple by the way we can divide this emergency light circuit into two sections.
Circuit Diagram of : Click to enlarge
1. Charging section
The charging section consist of a the input 9vdc from the adapter transformer (not shown in the circuit) is fed to the input of the adjustable voltage regulator LM317. By adjusting the preset RV1, we can adjust the output voltage of the regulator IC. The output voltage can be adjusted to deliver the charging voltage. When the battery gets charged above 5.2 volt, the zenar diode ZD1 conducts and the LM317 IC stops deivering charging voltage.
2. Automatic light and mains detection
This emergency light circuit design can behave automatically to switch off the LEDs when there is power supply available on the mains. So a BC558 PNP transistor done this job of shutting down the power supply to further circuit elements when there is mains available. The transistor BC548 is usually turn on during day time because the resistance of LDR is low when there is light in the room. When outside light falls, the LDR resistance will become high, this turn off the transistor Q3. So a positive voltage is fed to the base of LED driver transistor SL100 and the transitor turned on by completing circuit through white LEDs on its emitter terminal.
Note:
- The zenar diode can be chosen accoring to battery charctersitics
- The preset RV2 can be varied to get the right LDR light sensing.
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8 comments:
Plz clearly mention the value of R1. Is it 15 ohms or 15K ohms...???
thX
@Haris Irfan,
It's a mistake from me, the R1 is of 150 Ohms. The image has been re-uploaded.Thank you
can u give me a simple fm transmitter circuit of any frequency
can u give me a simple fm transmitter circuit of any frequency
with complete design
hi,, is there any replacement for sk/sl/cl100??.. can i use a general purpose transistor??? im from philippines.. tnx..
Of course..you can use. It't only for to drive the led's : for experimental setup, you can use GP transistor.
if i will put an indicator like LEDs where will i place them???,, to indicate that the battery is charging or is in fully charged... i like to put a green led for the "fully charged" and a red led for the charging.. tnx..
thanx
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