----- Original Message -----=20 From: "RussellMc" To: "Microcontroller discussion list - Public." Sent: Sunday, June 12, 2011 6:36 PM Subject: Re: [EE] My very simple optical guitar tuner board - please=20 giveadvice >> Purpose of the reservoir cap is to hold charge and deliver it >> with more of a force than a weak battery could. I am assuming that the tuner runs the LEDs continuously at the tuning=20 frequency while it is in use. If that is the case then there is no sense in= =20 using a really large cap. You only need one to hold enough charge for one=20 pulse of the LED. You certainly aren't likely to have one big enough to hol= d=20 a charge through a whole tuning cycle, which I am guessing will be at least= =20 several seconds. -- Bob Ammerman RAm Systems --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .