Multiple power supplies: newbie
Interactives
Posts: 83
Hello smart people, I'm somewhat new to this crazy world of forum posting, so please bear with me. I've been assigned to construct a device that, when triggered by a push button, starts a series of lights, each with different DC voltages, that will stay on for a few seconds, and then turn off. Sounds easy, right? Well... I've read enough to know that I need to run each light off of a transistor- relay coupling. My question is: the pushbutton is running active high from VDD (5V)- is there enough power in the stamps 5V output to run the 4 relays I need to trigger from the VDD as well? I'm assuming that I would hook up these four relays in parallel, so that the voltage remains 5V at each transistor- relay point. The tricky thing is that each relay will fire in series- relay one goes on, stays on, then relay two goes on.. etc. Does this mean that the power consumed will be increasing in increments, slowly killing the stamp? I guess the other option for me is having a isolated power source for the relays- but I've already got like 5 or so isolated power source for the lights the relays will be running. It 's getting ridiculous with all these crazy power sources!! Please help. Me no smart.
Comments
Not a problem, this question is asked all the time, look in the forums for it.
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=183414&Row=468736&Site=US
http://www.toshiba.com/taec/components/Datasheet/ULN2804AP.pdf
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Post Edited (nick bernard) : 3/2/2005 8:41:41 PM GMT