At 02:15 PM 2/11/2012, Nathan House wrote: >I'm burning through batteries like nobody's business and think it's >high time I purchased a power supply. >http://www.ebay.com/itm/Precision-Lab-PS305D-Variable-30V-5A-DC-Power-Supp= ly-/120716204084?pt=3DLH_DefaultDomain_0&hash=3Ditem1c1b3f1834 I've had very good luck with similar power supplies. I have single,=20 dual and triple supplies - most are made in Asia and all have been excellen= t. The better of these use linear regulators and have relays that select=20 the appropriate tap on the power transformer so as to limit power=20 dissipation in the pass elements. You will relays clicking as you=20 change the voltage knob from min to max on these units - that noise=20 is a GOOD thing to hear. Although the price on the unit that you linked to is reasonable, I've=20 seen better prices on similar units. It might take an hour or more=20 searching to find these deals (eBay is great) but you can save=20 significant cash if you spend the time. Be sure, though, to include=20 shipping in each seller's total cost before doing your comparisons. You CAN make your own power supply - its a great early project that=20 will last you for years. I built several small power supplies while=20 I was a teenager (or even before) - the best units were based on=20 LM723 regulator chips with external pass devices. You can build a 1A=20 or 2A supply easily but the heatsink starts to get HUGE as you exceed=20 2A. And - its hard to find power transformers that have multiple=20 secondary taps at the proper ratios to do any good for auto-switching=20 into your linear regulator. Most transformers have an available=20 center-tap but you really need 4 taps or so to keep the heat sink small. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .