Shop OBEX P1 Docs P2 Docs Learn Events
Reverse Polarity Protection — Parallax Forums

Reverse Polarity Protection

ArchiverArchiver Posts: 46,084
edited 2004-06-21 19:40 in General Discussion
On Mon, 22 Apr 2002 16:27:26 -0000, sznavor23 wrote:
>hi there,
>
>
>you do this in the program to run the other banks...
>on the top of the first program put this (replacing the example
>names with your file names)
>
>'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
>
>leave the ' character there dont take it out
>
>
>then on the end of the first memory bank of code you just put run 1
>
>then it will run the next program
>
>
>remember you start on program 0 and not program 1
>
>on all the banks of program you copy and paste the above (replacing
>my example names with YOUR file names), so it knows to associate ALL
>·the code to the stamp project
>
>'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
>
>on each bank end you just run the next bank, after you fill up bank
>0 you use run 1, after you fill up bank 1 you use run 2.......etc.
>
>
>steve
>
>
>hope that wasnt TOO confusing....sorry.
>
>
Hello,

I'm controlling some serial motor controllers with a BS2p and, by accident, I've
connected the motor power to the amplifier reversed which blows up the amplifier
(litterally!). I'm looking for a good way to protect the controller from
reverse polarity. My first thought was to use a bridge rectifier or just a fat
rectifier diode in line, but there is an undesirable voltage drop.

Any suggestions?

Thanks,
Stewart

--
Stewart Mayer, stewlist@k... on 04/22/2002

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-04-23 00:22
    Hi Stewart:

    Bet that smelled!!!! Every diode has a voltage drop usually .6 to 1 volt.
    Might try something more mechanical, a keyed connector that does not allow
    it to be reversed.

    Good Luck and keep smoking!!!

    Eric
    Original Message
    From: "Stewart Mayer" <stewlist@k...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, April 22, 2002 6:47 PM
    Subject: [noparse][[/noparse]basicstamps] Reverse Polarity Protection


    On Mon, 22 Apr 2002 16:27:26 -0000, sznavor23 wrote:
    >hi there,
    >
    >
    >you do this in the program to run the other banks...
    >on the top of the first program put this (replacing the example
    >names with your file names)
    >
    >'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
    >
    >leave the ' character there dont take it out
    >
    >
    >then on the end of the first memory bank of code you just put run 1
    >
    >then it will run the next program
    >
    >
    >remember you start on program 0 and not program 1
    >
    >on all the banks of program you copy and paste the above (replacing
    >my example names with YOUR file names), so it knows to associate ALL
    > the code to the stamp project
    >
    >'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
    >
    >on each bank end you just run the next bank, after you fill up bank
    >0 you use run 1, after you fill up bank 1 you use run 2.......etc.
    >
    >
    >steve
    >
    >
    >hope that wasnt TOO confusing....sorry.
    >
    >
    Hello,

    I'm controlling some serial motor controllers with a BS2p and, by accident,
    I've connected the motor power to the amplifier reversed which blows up the
    amplifier (litterally!). I'm looking for a good way to protect the
    controller from reverse polarity. My first thought was to use a bridge
    rectifier or just a fat rectifier diode in line, but there is an undesirable
    voltage drop.

    Any suggestions?

    Thanks,
    Stewart

    --
    Stewart Mayer, stewlist@k... on 04/22/2002



    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.


    Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2002-04-23 02:05
    A single MOSFET may be connected in series and will not conduct if reverse
    powered and without any drop if in the right direction.
    ACJacques

    Stewart Mayer gravada:

    > On Mon, 22 Apr 2002 16:27:26 -0000, sznavor23 wrote:
    > >hi there,
    > >
    > >
    > >you do this in the program to run the other banks...
    > >on the top of the first program put this (replacing the example
    > >names with your file names)
    > >
    > >'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
    > >
    > >leave the ' character there dont take it out
    > >
    > >
    > >then on the end of the first memory bank of code you just put run 1
    > >
    > >then it will run the next program
    > >
    > >
    > >remember you start on program 0 and not program 1
    > >
    > >on all the banks of program you copy and paste the above (replacing
    > >my example names with YOUR file names), so it knows to associate ALL
    > > the code to the stamp project
    > >
    > >'{$STAMP BS2SX,program1.bsx,program2.bsx,program3.bsx}
    > >
    > >on each bank end you just run the next bank, after you fill up bank
    > >0 you use run 1, after you fill up bank 1 you use run 2.......etc.
    > >
    > >
    > >steve
    > >
    > >
    > >hope that wasnt TOO confusing....sorry.
    > >
    > >
    > Hello,
    >
    > I'm controlling some serial motor controllers with a BS2p and, by accident,
    I've connected the motor power to the amplifier reversed which blows up the
    amplifier (litterally!). I'm looking for a good way to protect the controller
    from reverse polarity. My first thought was to use a bridge rectifier or just a
    fat rectifier diode in line, but there is an undesirable voltage drop.
    >
    > Any suggestions?
    >
    > Thanks,
    > Stewart
    >
    > --
    > Stewart Mayer, stewlist@k... on 04/22/2002
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2002-04-23 02:10
    Greetings,
    Place a fuse in the power lead. Then place a high current diode
    (reverse biased) behind the fuse to ground. Should you ever connect the
    power leads backwards again, the diode will conduct and blow the fuse.
    Since the diode will do it's best to clamp the voltage to about .7 volts,
    your motor controller won't see more than that voltage and only briefly.

    --- Jay Nugent


    > I'm controlling some serial motor controllers with a BS2p and, by accident,
    > I've connected the motor power to the amplifier reversed which blows up the
    > amplifier (litterally!). I'm looking for a good way to protect the
    > controller from reverse polarity. My first thought was to use a bridge
    > rectifier or just a fat rectifier diode in line, but there is an undesirable
    > voltage drop.
    >
    > Any suggestions?
    >
    > Thanks,
    > Stewart
    >
    > --
    > Stewart Mayer, stewlist@k... on 04/22/2002
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >


    "Those that sacrifice essential liberty to obtain a little temporary safety
    deserve neither liberty nor safety." -- Ben Franklin (1759)
    +
    +
    | Jay Nugent jjn@n... (734)971-1076 (734)971-4529/Fax |
    | Nugent Telecommunications [noparse][[/noparse]www.nuge.com] (734)649-0850/Cell |
    | Internet Consulting/Linux SysAdmin/Engineering & Design/ISP Reseller |
    | ISP Monitoring [noparse][[/noparse]www.ispmonitor.net] ISP & Modem Performance Monitoring |
    | Web-Pegasus [noparse][[/noparse]www.webpegasus.com] Web Hosting/DNS Hosting/Shell Accts|
    | LinuxNIC, Inc. [noparse][[/noparse]www.linuxnic.net] Registrar of the .linux TLD |
    +
    +
    9:01pm up 81 days, 10:26, 10 users, load average: 0.00, 0.00, 0.00
  • ArchiverArchiver Posts: 46,084
    edited 2002-04-23 14:24
    Thanks guys for all the suggestions. I already have polarized plugs, but this
    thing is going to be powered from dozens of power sources over the next few
    years and I know that an intern will sometime make a reverse connection if I
    don't do it myself. I like the mosfet idea, but I would hate to have to replace
    it if static electricity killed it. I also like the classic fuse idea, I think
    I'll try to implement that if I can find some panel mount fuse holders at
    digikey.

    Thanks,
    Stewart

    On Mon, 22 Apr 2002 21:10:25 -0400 (EDT), Jay Nugent wrote:
    >Greetings, Place a fuse in the power lead. ·Then place a high
    >current diode (reverse biased) behind the fuse to ground. ·Should
    >you ever connect the power leads backwards again, the diode will
    >conduct and blow the fuse. ·Since the diode will do it's best to
    >clamp the voltage to about .7 volts, your motor controller won't see
    >more than that voltage and only briefly.
    >
    >--- Jay Nugent
    >
    >
    >>I'm controlling some serial motor controllers with a BS2p and, by
    >>accident, I've connected the motor power to the amplifier reversed
    >>which blows up the amplifier (litterally!). ·I'm looking for a good
    >>way to protect the controller from reverse polarity. ·My first
    >>thought was to use a bridge rectifier or just a fat rectifier diode
    >>in line, but there is an undesirable voltage drop.
    >>
    >>Any suggestions?
    >>
    >>Thanks, Stewart
    >>
    >>--
    >>Stewart Mayer, stewlist@k... on 04/22/2002
    >>
    >>
    >>
    >>To UNSUBSCRIBE, just send mail to: basicstamps
    >>-unsubscribe@yahoogroups.com from the same email address that you
    >>subscribed. ·Text in the Subject and Body of the message will be
    >>ignored.
    >>
    >>
    >>Your use of Yahoo! Groups is subject to
    >>http://docs.yahoo.com/info/terms/
    >>
    >>
    >>
    >>
    >>
    >>To UNSUBSCRIBE, just send mail to: basicstamps
    >>-unsubscribe@yahoogroups.com from the same email address that you
    >>subscribed. ·Text in the Subject and Body of the message will be
    >>ignored.
    >>
    >>
    >>Your use of Yahoo! Groups is subject to
    >>http://docs.yahoo.com/info/terms/
    >>
    >>
    >
    >
    >"Those that sacrifice essential liberty to obtain a little temporary
    >safety deserve neither liberty nor safety." ·-- Ben Franklin (1759)
    >+
    >
    >----+ | Jay Nugent · jjn@n... · ·(734)971-1076 · ·(734)971
    >-4529/Fax | | Nugent Telecommunications ·[noparse][[/noparse]www.nuge.com] · · (734)649
    >-0850/Cell | | · Internet Consulting/Linux SysAdmin/Engineering &
    >Design/ISP Reseller | | ISP Monitoring [noparse][[/noparse]www.ispmonitor.net] ISP &
    >Modem Performance Monitoring | | Web-Pegasus · ·[noparse][[/noparse]www.webpegasus.com]
    >Web Hosting/DNS Hosting/Shell Accts| | LinuxNIC, Inc.
    >[noparse][[/noparse]www.linuxnic.net] · Registrar of the .linux TLD | +
    >
    >----+ 9:01pm ·up 81 days, 10:26, 10 users, ·load average: 0.00,
    >0.00, 0.00
    >
    >
    >To UNSUBSCRIBE, just send mail to: basicstamps
    >-unsubscribe@yahoogroups.com from the same email address that you
    >subscribed. ·Text in the Subject and Body of the message will be
    >ignored.
    >
    >
    >Your use of Yahoo! Groups is subject to
    >http://docs.yahoo.com/info/terms/
    >
    >


    --
    Stewart Mayer, stewlist@k... on 04/23/2002
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-29 15:26
    I know there are a few simple circuits for reverse battery hookup
    protection. I've seen them, think I can find them? Been looking
    through the net and archives, no luck.
    Anybody have a good cheep one for 6-12Vdc?
    Thanks
    Ian
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-29 15:30
    The simplest is a diode, like the 1N400x series. You just need to get
    one beefy enough to handle the amount of current that will flow through
    it, and keep in mind that it will drop about 0.7 volts.

    + Input
    >|
    circuit

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: iphillipsca [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=w93_aWtc5Oy9u9TncVsD3N9wc5s5QUHvMzoHsgh-FjNy55gVX-G4qFn_igSOgvRGMzRMezDhruBtOAvHwg]iphillips@s...[/url
    Sent: Monday, December 29, 2003 9:26 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Reverse polarity protection


    I know there are a few simple circuits for reverse battery hookup
    protection. I've seen them, think I can find them? Been looking
    through the net and archives, no luck.
    Anybody have a good cheep one for 6-12Vdc?
    Thanks
    Ian


    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject
    and Body of the message will be ignored.


    Yahoo! Groups Links

    To visit your group on the web, go to:
    http://groups.yahoo.com/group/basicstamps/

    To unsubscribe from this group, send an email to:
    basicstamps-unsubscribe@yahoogroups.com

    Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/




    This message has been scanned by WebShield. Please report SPAM to
    abuse@p....
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-29 15:45
    Or if he is using 6v battery power and can not afford the diode drop

    +Vin ---(~.25amp fuse)
    circuit
    |
    _
    ^ diode
    |
    |
    Gnd.

    Simply use a fuse suitable for the load, and a diode that is rated for more
    current than the fuse.

    KF4HAZ - Lonnie

    From: "Jon Williams" <jwilliams@p

    > The simplest is a diode, like the 1N400x series. You just need to get
    > one beefy enough to handle the amount of current that will flow through
    > it, and keep in mind that it will drop about 0.7 volts.
    >
    > + Input
    >|
    circuit
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: iphillipsca [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-SaIenQmhJxKcjkcF27O8kv_hI9_KdrvKE2jEaZcdQYYxMnfd8mqsr1AyozzF-gLjkDxZTW7NxvQPpmgUBSvgrc]iphillips@s...[/url
    > Sent: Monday, December 29, 2003 9:26 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Reverse polarity protection
    >
    >
    > I know there are a few simple circuits for reverse battery hookup
    > protection. I've seen them, think I can find them? Been looking
    > through the net and archives, no luck.
    > Anybody have a good cheep one for 6-12Vdc?
    > Thanks
    > Ian
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-29 16:21
    Just to go one further, could the diode be an LED? Lights when reversed.

    Ian

    Original Message
    From: FalconWireless Tech Support - KF4HAZ
    [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=yzJUj0YWvgK-qpAPveLy_gkK6-YH4HcqL_-7fcm3mbaIaTHHKCh4DKf96Vtpi9Pu_0gPP7JZjBA6HfvJJqMuo_zFi-XIkg]techsupport@f...[/url
    Sent: December 29, 2003 10:46 AM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Reverse polarity protection

    Or if he is using 6v battery power and can not afford the diode drop

    +Vin ---(~.25amp fuse)
    circuit
    |
    _
    ^ diode
    |
    |
    Gnd.

    Simply use a fuse suitable for the load, and a diode that is rated for
    more current than the fuse.

    KF4HAZ - Lonnie

    From: "Jon Williams" <jwilliams@p

    > The simplest is a diode, like the 1N400x series. You just need to get
    > one beefy enough to handle the amount of current that will flow
    through
    > it, and keep in mind that it will drop about 0.7 volts.
    >
    > + Input
    >|
    circuit
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: iphillipsca [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=84lXdQ89pZeFd44aaqJ0G9JHe-t3u8zWc47SzgNsTupyCOlYgdQZlB9icd6nx0R18yZABh2T0zsJ7VkWbwj8Ow]iphillips@s...[/url
    > Sent: Monday, December 29, 2003 9:26 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Reverse polarity protection
    >
    >
    > I know there are a few simple circuits for reverse battery hookup
    > protection. I've seen them, think I can find them? Been looking
    > through the net and archives, no luck.
    > Anybody have a good cheep one for 6-12Vdc?
    > Thanks
    > Ian



    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject
    and Body of the message will be ignored.


    Yahoo! Groups Links

    To visit your group on the web, go to:
    http://groups.yahoo.com/group/basicstamps/

    To unsubscribe from this group, send an email to:
    basicstamps-unsubscribe@yahoogroups.com

    Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-29 18:22
    That would not provide the protection.
    By the time you add the current limiting resistor the circuit would see full
    reverse voltage and the LED would light to tell you the
    circuit was fried!
    Also the fuse would not blow.

    KF4HAZ - Lonnie

    From: "Ian Phillips" <iphillips@s

    > Just to go one further, could the diode be an LED? Lights when reversed.
    >
    > Ian
    >
    >
    Original Message
    > From: FalconWireless Tech Support - KF4HAZ
    > [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=svtZjEh8WM6HcKy3Z0IqkEFeq7-4JfnRPjoiimLBZWj1-AE29F16WGGn3bciuKroCWABgS6P4W8j868wxq00EdoNm95v7Y1NCw]techsupport@f...[/url
    > Sent: December 29, 2003 10:46 AM
    > To: basicstamps@yahoogroups.com
    > Subject: Re: [noparse][[/noparse]basicstamps] Reverse polarity protection
    >
    > Or if he is using 6v battery power and can not afford the diode drop
    >
    > +Vin ---(~.25amp fuse)
    circuit
    > |
    > _
    > ^ diode
    > |
    > |
    > Gnd.
    >
    > Simply use a fuse suitable for the load, and a diode that is rated for
    > more current than the fuse.
    >
    > KF4HAZ - Lonnie
    >
    >
    From: "Jon Williams" <jwilliams@p
    >
    > > The simplest is a diode, like the 1N400x series. You just need to get
    > > one beefy enough to handle the amount of current that will flow
    > through
    > > it, and keep in mind that it will drop about 0.7 volts.
    > >
    > > + Input
    >|
    circuit
    > >
    > > -- Jon Williams
    > > -- Applications Engineer, Parallax
    > > -- Dallas Office
    > >
    > >
    > >
    Original Message
    > > From: iphillipsca [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RhGqyYPSwAAK-yq9I103vmHJXOdka-uJM_cVBbHZfTYYIGnXUhmp_HU9bnc3Xsbgbuj1MClvF3H98GSwXQ]iphillips@s...[/url
    > > Sent: Monday, December 29, 2003 9:26 AM
    > > To: basicstamps@yahoogroups.com
    > > Subject: [noparse][[/noparse]basicstamps] Reverse polarity protection
    > >
    > >
    > > I know there are a few simple circuits for reverse battery hookup
    > > protection. I've seen them, think I can find them? Been looking
    > > through the net and archives, no luck.
    > > Anybody have a good cheep one for 6-12Vdc?
    > > Thanks
    > > Ian
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-19 02:21
    In the files section of our group I uploaded a schematic that will protect a
    circuit from reverse polarity connection.

    There is no explination on the schematic, I will explain here.

    The circuit uses a DPDT relay and a diode.

    When the correct polarity is applied to the circuit, current through the
    relay coil cause the NO contacts of the coil to close supplying power to your
    circuit with the correct polarity.

    The LED is reverse biased and off.

    If the polarity to the circuit is connected incorrectly, the relay coil does
    not close due to the reverse biased diode, and the LED will turn on
    indicating the connections to the circuit are incorrect.

    There is no diode across the relay coil as there is no component such as a
    transistor that will be damaged when the circuit connections are disconnected.

    Ken


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-19 02:35
    In a message dated 6/18/2004 10:21:10 PM Pacific Standard Time, SmartDim
    writes:

    There is no diode across the relay coil as there is no component such as a
    transistor that will be damaged when the circuit connections are disconnected.

    Ken



    But there should be a diode across the relay coil.......What was I thinking
    of?????

    Ken



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-19 13:56
    Thanks, Looks like a simple but clever idea. I can think of numerous ways
    to use a circuit of this type.

    Richard
    Original Message
    From: <smartdim@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Saturday, June 19, 2004 12:35 AM
    Subject: Re: [noparse][[/noparse]basicstamps] Reverse Polarity Protection


    >
    >
    > In a message dated 6/18/2004 10:21:10 PM Pacific Standard Time, SmartDim
    > writes:
    >
    > There is no diode across the relay coil as there is no component such as
    a
    > transistor that will be damaged when the circuit connections are
    disconnected.
    >
    > Ken
    >
    >
    >
    > But there should be a diode across the relay coil.......What was I
    thinking
    > of?????
    >
    > Ken
    >
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
    > [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-21 19:40
    why not just put a diode bridge on the input?

    that will allow you to use ac or dc?


    --- In basicstamps@yahoogroups.com, "Richard" <rwskinner@a...> wrote:
    > Thanks, Looks like a simple but clever idea. I can think of
    numerous ways
    > to use a circuit of this type.
    >
    > Richard
    >
    Original Message
    > From: <smartdim@a...>
    > To: <basicstamps@yahoogroups.com>
    > Sent: Saturday, June 19, 2004 12:35 AM
    > Subject: Re: [noparse][[/noparse]basicstamps] Reverse Polarity Protection
    >
    >
    > >
    > >
    > > In a message dated 6/18/2004 10:21:10 PM Pacific Standard Time,
    SmartDim
    > > writes:
    > >
    > > There is no diode across the relay coil as there is no component
    such as
    > a
    > > transistor that will be damaged when the circuit connections are
    > disconnected.
    > >
    > > Ken
    > >
    > >
    > >
    > > But there should be a diode across the relay coil.......What was
    I
    > thinking
    > > of?????
    > >
    > > Ken
    > >
    > >
    > >
    > > [noparse][[/noparse]Non-text portions of this message have been removed]
    > >
    > >
    > >
    > > To UNSUBSCRIBE, just send mail to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > > from the same email address that you subscribed. Text in the
    Subject and
    > Body of the message will be ignored.
    > >
    > > Yahoo! Groups Links
    > >
    > >
    > >
    > >
    > >
    > >
    > > [noparse][[/noparse]Scanned by AwesomeNet Anti-Virus]
    > >
    > >
Sign In or Register to comment.