Fustrated Beginner - Just To Be Safe

Archiver · 2000-10-18 20:03

Hey Thanks For The Help,

I remember reading this section before.

Just so I'm sure I have it straight, what I going to do is the
following:

connect bsII pin to NPN transistor's base with a 1K resistor
connect VSS- to emitter of transistor
connect collector of transistor to relay
connect VDD+ to relay
connect a diode from one part of the coil to the other

The VSS and VDD I'm using is comming from the stamps carrier board
outputting 5V.

Thanks, again
The site is very helpful. I have it bookmarked.

--- In basicstamps@egroups.com, "Al Williams" <alw@a...> wrote:
> Read http://www.al-williams.com/wd5gnr/stampfaq.htm#s2.5
>
> and http://www.al-williams.com/wd5gnr/stampfaq.htm#s2.29
>
> The idea is to connect the base of a 2N2222 (or similar) transistor
to the
> Stamp via a resistor (say 1K or so). The emitter goes to ground and
the
> collector goes to one end of the relay coil. The other end goes to
+V.
> Here's the tricky part. Take a diode (1N914, 1N4148, even an
1N4001) and put
> the banded end to the +V end of the coil and the non-banded end to
the other
> end of the coil (the collector end).
>
> When you set the Stamp pin high, the transistor will go into
saturation. The
> Vce will be about .2V or so and the relay should snap on. When the
pin goes
> low, the transistor falls out of saturation, Vce climbs to about 5V
and the
> coil is off. Without the diode, the switching time of the
transistor can
> create a huge voltage in the coil (inductors generate voltage in
proportion
> to time variations in voltage -- that's why they resist AC but not
DC).
> That's what is blowing your transistor.
>
> You can also use a MOSFET, but the old transistor circuit is a well-
known
> design.
>
> Regards,
>
> Al Williams
> AWC
> *Expand your Stamp I/O: http://www.al-williams.com/awce/pak3.htm
>
>
> >

Original Message

> > From: ContactMe@S... [noparse][[/noparse]mailto:ContactMe@S...]
> > Sent: Wednesday, October 18, 2000 12:05 PM
> > To: basicstamps@egroups.com
> > Subject: [noparse][[/noparse]basicstamps] Fustrated Beginner
> >
> >
> >
> > Hello All, While I'm sending this message, I am searching
> > through the archives for an answer that is probably obvious to
> > most of you. I am fairly new to electronics and
> > stamping. Here is the question All I am trying to
> > do is drive a relay with my BSII. I've tried many ways but all
> > have failed. Currently, I must not very good with
> > shematics b/c I have looked at some but it still does not work.
> > The relay is a simple SPDT rely I picked up from RadioShack
> > that turns on/off at 5V. I tried using two stamp pins, one
> > low and one high. I tried using a NPN and a PNP transistor
> > connected to a stamp pin but nothing seems to turn that coil
> > on. If I take a 6v battery and connect it directly to the coil,
> > it works. By the way most of my transistors seem to blow
> > up. Can anyone give help in laymens terms as to how to go
> > about connecting the wires. Right now I'm using the BSII with
> > it's carrier board from the kit and and an addit!
> > ional breadboard. Sorry for such a simple question. Any
> > help is greatly appreciated. :-) 
> >

> >

> >
> > Visit http://www.ChurchItinerary.com today!!
> >
> >

Archiver · 2000-10-18 20:16

Two points:

1) The diode's orientation is very important. Banded end to +V, non-banded
end to the side that connects to the collector (of course, +V is on one side
of the relay coil and the collector is on the other side).

2) The Stamp's regulator is not suitable for a lot of current. This is
especially true with the BS2SX. Your relay coil requires a certain amount of
current -- be sure you aren't trying to draw too much. If the board you are
using has an external regulator, that's probably OK.

Regards,

Al Williams
AWC
*Expand your Stamp I/O: http://www.al-williams.com/awce/pak3.htm

>

Original Message

> From: ContactMe@S... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=UHKtdKDP509GL8F2mPdKO0fub2gNjjaV65gJldTM4w5VGdt5WB3Et48QPo6LN5eH5pn3GtBw0bp_fJ8RnUBcj8z8ZSaO]ContactMe@S...[/url
> Sent: Wednesday, October 18, 2000 2:04 PM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Fustrated Beginner - Just To Be Safe
>
>
> Hey Thanks For The Help,
>
> I remember reading this section before.
>
> Just so I'm sure I have it straight, what I going to do is the
> following:
>
> connect bsII pin to NPN transistor's base with a 1K resistor
> connect VSS- to emitter of transistor
> connect collector of transistor to relay
> connect VDD+ to relay
> connect a diode from one part of the coil to the other
>
> The VSS and VDD I'm using is comming from the stamps carrier board
> outputting 5V.
>
> Thanks, again
> The site is very helpful. I have it bookmarked.
>
>
> --- In basicstamps@egroups.com, "Al Williams" <alw@a...> wrote:
> > Read http://www.al-williams.com/wd5gnr/stampfaq.htm#s2.5
> >
> > and http://www.al-williams.com/wd5gnr/stampfaq.htm#s2.29
> >
> > The idea is to connect the base of a 2N2222 (or similar) transistor
> to the
> > Stamp via a resistor (say 1K or so). The emitter goes to ground and
> the
> > collector goes to one end of the relay coil. The other end goes to
> +V.
> > Here's the tricky part. Take a diode (1N914, 1N4148, even an
> 1N4001) and put
> > the banded end to the +V end of the coil and the non-banded end to
> the other
> > end of the coil (the collector end).
> >
> > When you set the Stamp pin high, the transistor will go into
> saturation. The
> > Vce will be about .2V or so and the relay should snap on. When the
> pin goes
> > low, the transistor falls out of saturation, Vce climbs to about 5V
> and the
> > coil is off. Without the diode, the switching time of the
> transistor can
> > create a huge voltage in the coil (inductors generate voltage in
> proportion
> > to time variations in voltage -- that's why they resist AC but not
> DC).
> > That's what is blowing your transistor.
> >
> > You can also use a MOSFET, but the old transistor circuit is a well-
> known
> > design.
> >
> > Regards,
> >
> > Al Williams
> > AWC
> > *Expand your Stamp I/O: http://www.al-williams.com/awce/pak3.htm
> >
> >
> > >

Original Message

> > > From: ContactMe@S... [noparse][[/noparse]mailto:ContactMe@S...]
> > > Sent: Wednesday, October 18, 2000 12:05 PM
> > > To: basicstamps@egroups.com
> > > Subject: [noparse][[/noparse]basicstamps] Fustrated Beginner
> > >
> > >
> > >
> > > Hello All, While I'm sending this message, I am searching
> > > through the archives for an answer that is probably obvious to
> > > most of you. I am fairly new to electronics and
> > > stamping. Here is the question All I am trying to
> > > do is drive a relay with my BSII. I've tried many ways but all
> > > have failed. Currently, I must not very good with
> > > shematics b/c I have looked at some but it still does not work.
> > > The relay is a simple SPDT rely I picked up from RadioShack
> > > that turns on/off at 5V. I tried using two stamp pins, one
> > > low and one high. I tried using a NPN and a PNP transistor
> > > connected to a stamp pin but nothing seems to turn that coil
> > > on. If I take a 6v battery and connect it directly to the coil,
> > > it works. By the way most of my transistors seem to blow
> > > up. Can anyone give help in laymens terms as to how to go
> > > about connecting the wires. Right now I'm using the BSII with
> > > it's carrier board from the kit and and an addit!
> > > ional breadboard. Sorry for such a simple question. Any
> > > help is greatly appreciated. :-) 
> > >

> > >

> > >
> > > Visit http://www.ChurchItinerary.com today!!
> > >
> > >
>
>
>

Fustrated Beginner - Just To Be Safe

Comments