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about stamp adapter

ArchiverArchiver Posts: 46,084
edited 2003-07-03 15:52 in General Discussion
i'm not in US and the country i'm living is using 240v supply.So ,i
had to buy my own adapter because the distributer there say they are
not responsible for this .i'm using the adapter which provide the
output voltage of 3-12v and 1200 mA .but when i see the original
adapter,it only gives 1000mA .I'm afraid that the 1200mA adapter will
spoil my whole inex-1000 circuit board .is it ok to use?
and is it true that the distributor of the stamp will not responsible
for providing the adapter which suits my country?thanks .

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-07-03 08:44
    --- In basicstamps@yahoogroups.com, "kaijiun83" <kaijiun83@y...>
    wrote:
    > i'm not in US and the country i'm living is using 240v supply.So ,i
    > had to buy my own adapter because the distributer there say they
    are
    > not responsible for this .i'm using the adapter which provide the
    > output voltage of 3-12v and 1200 mA .but when i see the original
    > adapter,it only gives 1000mA .I'm afraid that the 1200mA adapter
    will
    > spoil my whole inex-1000 circuit board .is it ok to use?
    > and is it true that the distributor of the stamp will not
    responsible
    > for providing the adapter which suits my country?thanks .

    Hi

    The 1200mA of your adapter are ok. This number just states what the
    adapter is capable to deliver. The voltage should be set to something
    from 6V to 9V. The current needed depends on your circuit. The stamp
    alone is satisfied with a few mA, but if you want do drive motors you
    may need up to 1000mA or more. 250mA should be sufficient for most
    needs.

    If your distributor does not provide power supplies (PSU), you have
    to buy one spearately or use one you already have if suitable.

    If your PSU is able to deliver more power than you need (e.g. 1200mA
    and you need just say 50mA) this is ok. But if your circuit yould
    require 2000mA your PSU will get hot and the voltage breaks down.

    Note that the voltage regulator on the INEX-1000 can deliver not more
    than about 1A, otherwise it would get to hot and burn out eventually.

    Regards
    Adrian
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-03 14:14
    With DC adapters, there are several things to care
    about, and a few not to care about.

    The first critical value is the voltage. If the
    supply does not deliver enough voltage, your
    project won't work. For the Stamp, the lowest
    the voltage can be is 6 volts DC.

    The first thing that is NOT so important is the
    current. Given a voltage, a stamp will only
    'pull' 50 mA or so, depending on what else it
    is driving. DC Adaptors are rated for the
    maximum current that can be 'pulled' from them.
    If you try to exceed this they overheat. If
    you stay less than this (ANY value less than
    this) everything is fine.

    So your 1200 mA DC supply may be more
    expensive, and CAN supply more current than
    required, but will ACTUALLY supply only the
    current that the Stamp is using.

    Note: Stamp boards are wired so the center
    pin of your power connector is POSITIVE, the
    outer 'sleeve' of the power connector is
    GROUND. This configuration is not a
    standard with all DC adapters. Verify with
    a volt meter BEFORE you plug it in to your
    board that you have this proper configuration.




    --- In basicstamps@yahoogroups.com, "kaijiun83" <kaijiun83@y...>
    wrote:
    > i'm not in US and the country i'm living is using 240v supply.So ,i
    > had to buy my own adapter because the distributer there say they
    are
    > not responsible for this .i'm using the adapter which provide the
    > output voltage of 3-12v and 1200 mA .but when i see the original
    > adapter,it only gives 1000mA .I'm afraid that the 1200mA adapter
    will
    > spoil my whole inex-1000 circuit board .is it ok to use?
    > and is it true that the distributor of the stamp will not
    responsible
    > for providing the adapter which suits my country?thanks .
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-03 14:48
    This is true of course. However, there is one other caveat. Typical wall
    warts are rated at their given load. So a 12V 1A wart will produce a lot
    more than 12V with a 50 or 100mA load. The Stamp has an upper limit on
    voltage and with any shunt regulator putting in a higher voltage will
    generate more heat.

    So be sure that you aren't feeding a very high voltage out of a nominal
    12V supply.

    Al Williams
    AWC
    * NEW: Real world I/O for C++, VB, Excel, Java, more...
    http://www.al-williams.com/gp3.htm


    > Given a voltage, a stamp will only
    > 'pull' 50 mA or so, depending on what else it
    > is driving. DC Adaptors are rated for the
    > maximum current that can be 'pulled' from them.
    > If you try to exceed this they overheat. If
    > you stay less than this (ANY value less than
    > this) everything is fine.
    >
    > So your 1200 mA DC supply may be more
    > expensive, and CAN supply more current than
    > required, but will ACTUALLY supply only the
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-03 15:52
    Very good point. I as amazed that my 9V DC 100 mA
    adapter from parallax was measured at 16V with no
    load. Note most voltages are specified
    as under load.

    I assume if your DC supply is too high, the
    regulator (that little 3-wire piece with the
    metal tab on it) will overheat, and then
    shutdown. This results in no damage, but can
    be a little alarming. If it's too hot to touch,
    somethings wrong.

    On the other hand, the BS2 has its own
    regulator, which is good for 6V to 9V or so,
    but has even more limited heat dissapation than
    a separate regulator would.

    I believe an external 7805 regulator can handle up
    to 24 volts as an input voltage without damage
    -- this should give you some flexibility,
    again as long as you don't exceed the
    heat dissapation.


    --- In basicstamps@yahoogroups.com, "Al Williams" <alw@a...> wrote:
    > This is true of course. However, there is one other caveat. Typical
    wall
    > warts are rated at their given load. So a 12V 1A wart will produce
    a lot
    > more than 12V with a 50 or 100mA load. The Stamp has an upper limit
    on
    > voltage and with any shunt regulator putting in a higher voltage
    will
    > generate more heat.
    >
    > So be sure that you aren't feeding a very high voltage out of a
    nominal
    > 12V supply.
    >
    > Al Williams
    > AWC
    > * NEW: Real world I/O for C++, VB, Excel, Java, more...
    > http://www.al-williams.com/gp3.htm
    >
    >
    > > Given a voltage, a stamp will only
    > > 'pull' 50 mA or so, depending on what else it
    > > is driving. DC Adaptors are rated for the
    > > maximum current that can be 'pulled' from them.
    > > If you try to exceed this they overheat. If
    > > you stay less than this (ANY value less than
    > > this) everything is fine.
    > >
    > > So your 1200 mA DC supply may be more
    > > expensive, and CAN supply more current than
    > > required, but will ACTUALLY supply only the
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