This is a linear regulator. Very old technology. A watt waster. It is dissipating the difference between the input voltage and the output voltage. That creates a lot of heat.
Gerald On Wed, Mar 5, 2014 at 1:13 PM, Dorian Levy <[email protected]> wrote: > 11.7V supply shouldn't be a problem because it can take up to 25V, but > I'll try a heat sink and see if that helps. > > > > On Wed, Mar 5, 2014 at 2:05 PM, Gerald Coley <[email protected]>wrote: > >> Because the regulator is going into thermal limit due to excessive heat >> dissipation. Make the 11.7V supply say 8V and it will run longer. The hole >> in the tab of the regulator is for the heat sink. >> >> Now, if the regulator is putting out 7V, then it could be the board. >> >> Gerald >> >> >> On Wed, Mar 5, 2014 at 1:02 PM, Dorian Levy <[email protected]>wrote: >> >>> Because the IC can't provide the required current without a heat sink? >>> Or because the BBB is going into thermal protection? A little insight into >>> why you would expect that would be appreciated." >>> On Mar 5, 2014 1:43 PM, "Gerald Coley" <[email protected]> wrote: >>> >>>> OK. Then what you are describing as your issue, i would expect to >>>> happen. >>>> >>>> Gerald >>>> >>>> >>>> >>>> On Wed, Mar 5, 2014 at 12:37 PM, Dorian Levy <[email protected]>wrote: >>>> >>>>> No heatsink 5V >>>>> On Mar 5, 2014 11:13 AM, "Gerald Coley" <[email protected]> >>>>> wrote: >>>>> >>>>>> Are you using a heatsink? Voltage? >>>>>> >>>>>> Gerald >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Mar 5, 2014 at 10:07 AM, Dorian Levy >>>>>> <[email protected]>wrote: >>>>>> >>>>>>> Addicore 5V 1.5A Positive Voltage Regulator L7805CV >>>>>>> >>>>>>> >>>>>>> On Wed, Mar 5, 2014 at 10:52 AM, Gerald Coley < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> That particular regulator can have different pinouts. I have been >>>>>>>> bitten before. So double check that based on the supplier. >>>>>>>> >>>>>>>> What voltage are you seeing on the output? I believe the best you >>>>>>>> can get out of that regulator without a big heatsink is maybe 500mA >>>>>>>> which >>>>>>>> is borderline for the BBB. You are dropping 6.7V across the regulator. >>>>>>>> >>>>>>>> Gerald >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Wed, Mar 5, 2014 at 8:57 AM, Dorian Levy >>>>>>>> <[email protected]>wrote: >>>>>>>> >>>>>>>>> On Mar 4, 2014 7:42 PM, "Gerald Coley" <[email protected]> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Can you share a schematic with me? I can't visualize what you are >>>>>>>>>> doing. >>>>>>>>>> >>>>>>>>>> Gerald >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Tue, Mar 4, 2014 at 5:05 PM, Dorian Levy < >>>>>>>>>> [email protected]> wrote: >>>>>>>>>> >>>>>>>>>>> I am building a robot that uses an 11.7V battery. I tried >>>>>>>>>>> attaching a 5V regulator to the T5(+)/T8(-) (pins with the >>>>>>>>>>> T6(SENSE) >>>>>>>>>>> bridged to T5 and a 10K resistor between T8(TS) and ground. The >>>>>>>>>>> board only >>>>>>>>>>> stays on for about thirty seconds then shuts down. Is it because of >>>>>>>>>>> the TS? >>>>>>>>>>> What type of thermistor does it use? Or should I try to use the >>>>>>>>>>> barrel jack >>>>>>>>>>> since it's not directly connected to a battery? >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> For more options, visit http://beagleboard.org/discuss >>>>>>>>>>> --- >>>>>>>>>>> You received this message because you are subscribed to the >>>>>>>>>>> Google Groups "BeagleBoard" group. >>>>>>>>>>> To unsubscribe from this group and stop receiving emails from >>>>>>>>>>> it, send an email to [email protected]. >>>>>>>>>>> For more options, visit https://groups.google.com/groups/opt_out >>>>>>>>>>> . >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> For more options, visit http://beagleboard.org/discuss >>>>>>>>>> --- >>>>>>>>>> You received this message because you are subscribed to a topic >>>>>>>>>> in the Google Groups "BeagleBoard" group. >>>>>>>>>> To unsubscribe from this topic, visit >>>>>>>>>> https://groups.google.com/d/topic/beagleboard/-Zb4VUlh5Mg/unsubscribe >>>>>>>>>> . >>>>>>>>>> To unsubscribe from this group and all its topics, send an email >>>>>>>>>> to [email protected]. >>>>>>>>>> >>>>>>>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>>>>>>> >>>>>>>>> -- >>>>>>>>> For more options, visit http://beagleboard.org/discuss >>>>>>>>> --- >>>>>>>>> You received this message because you are subscribed to the Google >>>>>>>>> Groups "BeagleBoard" group. >>>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>>> send an email to [email protected]. >>>>>>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> For more options, visit http://beagleboard.org/discuss >>>>>>>> --- >>>>>>>> You received this message because you are subscribed to a topic in >>>>>>>> the Google Groups "BeagleBoard" group. >>>>>>>> To unsubscribe from this topic, visit >>>>>>>> https://groups.google.com/d/topic/beagleboard/-Zb4VUlh5Mg/unsubscribe >>>>>>>> . >>>>>>>> To unsubscribe from this group and all its topics, send an 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https://groups.google.com/groups/opt_out. >>>>>> >>>>> -- >>>>> For more options, visit http://beagleboard.org/discuss >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "BeagleBoard" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>> >>>> -- >>>> For more options, visit http://beagleboard.org/discuss >>>> --- >>>> You received this message because you are subscribed to a topic in the >>>> Google Groups "BeagleBoard" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/beagleboard/-Zb4VUlh5Mg/unsubscribe. >>>> To unsubscribe from this group and all its topics, send an email to >>>> [email protected]. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You 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