2008-12-19-1931Z


MrCreditRepair.biz will fix your credit rating!

More experimenting with the solderless breadboard... what was I doing so long without one! And did another calculation on the correct amount of capacitance to use, this time just based on watts. Since with 4 .22uF caps I get 1.4V across a 50.0 ohm resistor, I need to compare that with the 6 volts used by the tent lamps, divided across 4 banks of 6 LEDs with a 33-ohm resistor feeding into each bank:

jcomeau@gdl:~$ python
Python 2.5.2 (r252:60911, Aug  8 2008, 09:22:44) 
[GCC 4.3.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> (6.0 ** 2) / (33.0 / 4)  # power is voltage squared over resistance
4.3636363636363633
>>> _ / ((1.4 ** 2) / 50.0)  # divided by the breadboard power
111.31725417439705
>>> _ / 0.88  # divided by the amount of capacitance used
126.49687974363302

So I need 120uF caps, not 22uF, if by some miracle I'm figuring it correctly this time. Those will be difficult to find in Mylar film. Might have to join two electrolytics in series with reverse parallel diodes and hope they work.

Back to blog or home page

last updated 2013-01-10 21:19:43. served from tektonic