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Yes, you are reading this right, a child safe flashlight that fades out by itself after letting go momentary switch, until you hit it again which will restore power to capacitor and turns on the light. :)
Values for transistors and lamp yet to be determined. .. datasheets are in below... yet no time. :(
You just needed to find a enclosure that serves two purposes:
1) bottom base to protect kids from unpredictable shocks or harms by touching the open circuit.
2) clear or diffused top that has momentary switch inside with the top.
How to use it?
This is controlled by a switch to two 1.5v batteries, and momentary switch to light up the lamp to maximum power, then let's go the switch, the charged capacitor will supply the power to the lamp, slowly draining the lamp's lumens to complete dark. This is about a minute or two. Do make the changes, but for kid's sakes, be careful with your modified circuit, but if this is for you to use, well, knock your socks off. ;)
Listed parts in below.
- You will need PR 2 type bulb or similar that has rated for 2.4V at half of a amp. (0.5A)
- capacitor - 10v 220uF
- Transistor 1 - S9015 G-002 datasheet: http://bit.ly/1N413rM
- Transistor 2 - S0050 B-011 datasheet: http://bit.ly/1KZWuN1
- Resistor 1 - 220ohm 5%
- Resistor 2 - 22ohm 5%
- Resistor 3 - 47kohm 5%
... yep, I destroyed a 30-years-old flashlight, just to salvage some parts I needed for later use. It was passed around in many generations and it finally broke, and I traced the problem to the capacitor. I have decided to keep this board for later project as well.
If I do get hands on new PR2 bulb that has cree on it, I probably can try to revive this flashlight.
Picture of product similar to what I have but different colour. http://i60.tinypic.com/1057k40.jpg
Picture of front board: http://i62.tinypic.com/156piqu.jpg
Picture of back board: http://i59.tinypic.com/10o4pyt.jpg
Similar idea of enclosure: https://www.sparkfun.com/products/9181
Last edited at: August 10, 2015.
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