to mimick a battery pack, probably you could connect some resistor in series, maybe 100ohm, or a little bit less (depending how much current that circuit actually uses) Together with a capacitor at the supply end that would also eliminate any short high voltage spikes, if those exist. On Thu, Jan 24, 2013 at 12:48 AM, William Bulley wrote: > According to IVP on Wed, 01/23/13 at 15:29: >> >> A fresh alkaline is 1.65V, so 3 would be as high as 4.95V (something >> you learn when powering logic off of batteries) > > Wow! Amazing! Who'da thunk? :-) > >> Perhaps measure the battery voltage during operation and after the >> unit stops working, also the current draw > > Okay, that sounds do-able. > >> Some designers are fiendishly clever, and can make a circuit work >> within a narrow window but don't give a hoot about battery life > > Yes, tell me about battery life... :-( > >> Similar to what Sean mentioned, I've seen a lot of people over at >> the laser LED sites using 2 batteries without active current limiting >> ("just stick 3V on it, you'll be fine"). There's 3V, and then there's >> 3V > > Heh... :-) > >> Ideally you'd want to characterise your tapestry with a PSU that >> has voltage and current settings. You can make a basic one with >> a couple of LM317s. One sets the voltage, another sets the current >> >> http://www.ti.com/lit/ds/symlink/lm117.pdf > > Very nice. Thanks! Boy that reference sure takes me back! :-) > >> Worth having a few in the parts box. Figure 36 shows how you use >> one as a current limiter - as an alternative to a resistor - to simulate >> the battery impedance > > I believe I do have a few in my parts box. Lots of reading to do... :-) > > Thanks again! > > Regards, > > web... > > -- > William Bulley Email: web@umich.edu > > 72 characters width template ----------------------------------------->| > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 KPL --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .