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BS2 power supply — Parallax Forums

BS2 power supply

NB_NesquikNB_Nesquik Posts: 35
edited 2012-10-31 19:43 in General Discussion
I know this probably sounds like a stupid question, but can I run my Basic Stamp Homework Board on a 12v power supply? I know that the BS2 itself can run at 12v, and there is a 5v regulater for the I/O pins. I just want to make sure that using 12v isnt going to harm the board. And I assume that if the board is run on 12v then Vin would also be 12v.

Thanks

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-10-31 18:34
    The issue with Vin > 9V is strictly heat dissipation. The regulator is rated for input voltages well in excess of 24V, but there's no significant heatsink on the Homework Board (other than the board itself). Anything over 5V will be dissipated as heat. If you have 3 LEDs plus the Stamp itself, that's a current draw of over 100mA (50mA + 3 x 20mA). With 12V - 5V = 7V of excess voltage, that's almost 3/4W of heat. If you hang other current drains on Vdd, the heat goes up. The regulator is rated for 1A, so you could get 7W of heat produced before the regulator shuts down due to over current. On the Homework Board, there's a single regulator for everything. If you pay attention to overall current drain, you could run the Stamp itself and some low current loads with a Vin = 12V.
  • Matt GillilandMatt Gilliland Posts: 1,406
    edited 2012-10-31 19:43
    Hi NB_Nesquik -
    One other thing to consider is that if you're using Vin on the Servo header, then you should use a 7.5vdc wall wart for power in. Although our servos are technically only rated for up to 6 vdc, I've ran them @ 7.5vdc for extended periods of time with no problems... at 8.2 or 8.3 you'll start smokin' servos - well, you know what happens when you let the "magic smoke out"...

    -MattG
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