The LED flashlights I bought in March from Amazon (but shipped from Hong Kong) arrived recently and I’ve had a chance to use them a bit. I paid $5.49 apiece, with free shipping, but I see that the price (as of June 8) has gone down to $4.30, These have a Cree Q5 emitter, and
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Here’s a picture of one of my flashlights, taken on the last day of 2006. I most likely had this posted on my late great watsonseblog. Maybe even here, too.
I measured the voltage of an unused Energizer Lithium AA cell, and found that it was 1.806 VDC, and another one measured 1.807V. Wow! Looked like the Energizer Bunny was running on jet fuel! These are very potent batteries. Their voltage is 20 percent higher than the normal AA cell. These lithium cells are supposed
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I was discussing using an incandescent lamp for a heater, where the amount of light is not important. I looked up some info on miniature lamps in the General Electric Miniature Lamp Catalog. Miniature lamps used to be inside of appliances, and cars, such as in the instrument panel, speedometer, glove box, etc. Now they
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I bought a few bricks of 40 AAA cells at Fry’s, mainly because they were only $4.20 each, or about ten cents apiece – that’s cheap! But I really needed AAA cells because of all the Fenix LD01 and similar flashlights I now have. But I have so many AAA cells that I’ll never be
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I forgot and left the AA cell in this circuit and I paid the price heavily. The AA cell leaked and corroded the battery holder so bad it’s going to the trash can. And by capillary action, the battery juice wicked up the black wire, around the switch and came out the end where the
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I started out using a single pole, single throw pushbutton switch from an old mouse for the switch on my Joule Thief with timeout circuit. But I changed it to a double throw switch. It’s simple to use the single throw switch to charge or discharge the timing capacitor and start the timeout. But if
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I built this light several years ago. I bought a LEDdynamics Micropuck 350 mA LED controller to drive a Luxeon Star 1W white LED. I used a black plastic project box, might have been from Radio Shack, as the case. I sawed the case in half, heightwise, so that it would fit in my pocket.
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I did this a few years ago and blogged it in my watsonseblog, now gone for more than a year. I guess it’s about time I did it again. The circuit is the two transistor circuit with a 2SD639 high current transistor for the output – it’s the same circuit I used in the flashlight
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