Showing posts with label emergency. Show all posts
Showing posts with label emergency. Show all posts

Wednesday, November 19, 2014

Simple LED Emergency Light Circuit


This LED emergency light project is simple, cheap and easy to build. The circuit do the charging of the battery and when the main source is not available such as in brownouts, the white LEDs automatically turn on. 
Initially, the voltage output  from 220V to 12V converter is fed to the input of LM317 regulator. Then this voltage is regulated down to 7.37V using 240 ohms and 1.2K resistor combination (see LM317 Calculator).
At this instant, the battery is in charging mode and the transistor Q1 is off. Indicator LED serves two purpose, one primarily is to give us idea that the battery is charging and another is to ensure that the Q1 is off.
During brownouts, the transistor Q1 is on and delivers current to 16 white LED of about 20mA each, thus a fully charged battery (6V/4.5Ah) can last up to 14 hours.

The charger has no built in over-current control but still it protects the battery from overcharging since the charging voltage is set only to 7.4V.


Project materials:
1pc - transformer - 220V to 12V-0-12V , center tap 12VA
16pc - 120 ohms resistor 1/4 W
16pc - white LED min 3V@30mA
1pc - red LED
1pc - 1000uF/25V electrolytic capacitor
3pc - 1N4001 diode
1pc - LM317 regulator
1pc - 1.5K resistor 1/4W
1pc - 240 ohms resistor 1/4W
1pc - 1.2k resistor 1/4W
1pc - 9012 pnp transistor or any of much higher capacity
1pc - 6V 4.5ah battery
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Thursday, October 30, 2014

Emergency Light Flashlight

3 in 1 - LED Night Light, LED Emergency Light and LED Flashlight; Length: 4.0". The Night Light has an Automatic Sensor which allows On at Dusk and Off at Dawn. The Emergency Light features an 8 Hour Battery Back Up. Convenient White Light Flashlight.

The light is not terribly sharp-witted but its first-class sufficient to facilitate you wont be real bumping into furniture all through a power outage. The light is by the side of its brightest at what time the power is rotten.
When its used having the status of a nightlight it is a not much dimmer but still upbeat adequate to perceive your way around.

Emergency
The intensity of the light motivation vary depending on how dark the opportunity is. during the belatedly afternoon while the sun is still outside it will live very dim but will perk up up being the extent becomes darker. Although here is a photo sensor on the light a loss of power preference aim the light on in spite of of how dark before light the area is.

The light stays on a bunch longer than the circular emergency plug concerning illumination with the aim of Ive used in the older and it looks a lot better than them. I carry out think it would look even better devoid of the flashlight part of the light and I would have a preference to grasp a version like with the aim of if theyd offer it.

Once plugging into a lookalike outlet it still leaves area intended for a lesser plug to progress into the outlet then to it.
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Tuesday, September 9, 2014

Versatile emergency lamp


versatile emergency lamp that can be operated in two modes (flasher and dimmer). The schema is based on the dual op-amp IC LM358.The dimmer and flasher mode can be selected by using the switch S1.






Notes.

* F1 should be a 2A fuse.
* L1 can be a 12V; 2A incandescent lamp.
* IC1 must be mounted on a holder.
* The schema can be assembled on a Vero board.
* Use a 12V battery for powering the schema.
* A heatsink must be fitted on transistor T2.
* S2 can be used as an ON/OFF switch.


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