If you run across a copy of Walter Jung's IC Timer Cookbook, there is as you'd expect a large selection of circuits for various timer chips. The most common basic chip is the 555, here's a link to get you going: http://www.555-timer-circuits.com/ Yrs, d On Wed, Aug 2, 2017 at 4:09 PM, Neil N <musomuso@gmail.com> wrote: > Thanks for that David. I've been so involved in other wiring projects, > haven't read this thread yet. > > Thats a sizeable cap! Image showing measurements: > > http://tinyurl.com/ybxpvnx5 > > I did see your comment on semiconductors being used for this type of > circuit. > > On 8/2/17, David Beierl <dbeierl@attglobal.net> wrote: > > > Osram DE3423 LED festoon lamp is one watt. If you want ten seconds of > > fading light at average half brightness that would require something like > > five watt seconds of storage in your capacitor. Say six or seven because > > of the threshold voltage of the LED. WS = C x V^2 / 2, so C = WS / (V^2 > / > > 2). So C = 7 ws / (12V^2 / 2) = 7 / 72 = ~0.1 farad or 100,000 uF. > > > > Here's one that would serve. It's nominal 40 mm diameter and 80 mm > length, > > and it costs ten bucks US in onesies. > > https://www.digikey.com/product-detail/en/united- > chemi-con/ESMH160VSN104MA80T/565-2624-ND/757837 > > > > Yrs, > > d > > > > > > > > On Wed, Aug 2, 2017 at 1:32 PM, Neil N <musomuso@gmail.com> wrote: > > > >> Thats great! So about 5 seconds eh? I'd think that for a festoon the > >> cap(s) would have to be much bigger. But maybe 3 of those small LED's > >> would be plenty? > >> > > > > > -- > Neil n > > Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca> > > 1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy> > > 1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/> > > Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay> > |
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