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Basic Stamp 2 voltages — Parallax Forums

Basic Stamp 2 voltages

flasherflasher Posts: 10
in BASIC Stamp
what is the difference between VDD and VIN?

Thanks

Flasher

Comments

  • ercoerco Posts: 20,257
    edited 2017-03-20 22:40
    Vdd is regulated 5.0 volts, which powers the BS2. If you have a clean 5V power supply, you can connect that to Vdd.

    Vin is the input for higher voltages, typically 6-9 volts. The onboard 5V regulator reduces that voltage down to 5.0V for the BS2. That same 5.0V will show up on the Vdd pin, so you may draw a bit of power off that pin to power some external circuitry if you need to.

    Vss is ground, or zero volts, connected to the battery minus terminal.

  • Hal AlbachHal Albach Posts: 747
    Somewhat loosely defined, (by me, and Wikipedia), Vdd is the term used for CMOS IC positive voltage supply and Vss is the ground connection. Vin is normally referred to the raw, unregulated input power to a regulating device. I always look at Vdd and Vss in electron flow theory as Vss is the source of electrons that flow into the IC and Vdd is the drain where electrons leave the IC.
  • ercoerco Posts: 20,257
    Nice description, Hal.

    And then there's Vcc used in some conventions...!
  • Hal AlbachHal Albach Posts: 747
    Why, thank you, Erco! Looks like we both hit the same Wikipedia page! I guess in some circles it is frowned upon to use a Vcc +5 Volts on a device that wants Vdd +5 Volts, like, "What difference, at this point, does it make?"
  • flasherflasher Posts: 10
    Thank you Hal and Erco. I'm actually trying to figure out the best place to cut into the 9V supply, since my circuit board lacks a switch in that circuit. Why not snip one lead at the battery holder and restore the circuit with a SPST switch?
  • Hal AlbachHal Albach Posts: 747
    That would certainly give you ON-OFF control, did you have other uses in mind for the Vin - 9 Volt supply?
  • flasherflasher Posts: 10
    Hal,
    I finally finished the in-line switch installation. When I say installation, it sounds like a major endeavor; for me, it was! It was like trying to thread a needle while somebody is shaking your rocker. I didn't know they made nuts and bolts that small.
    Oh-by-the-way, a few years ago, a large department store( Roses) closed in town and I found a bunch of RC cars and bought 7 of them for $5 each. I have had a lot of fun with them, tearing them apart and using the little transceiver to control other projects. The receiver has 13 transistors! I was not able to find out what part of China they were made in.
    73s
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