PRC as a amplifier in GPS question.

[Bill Bailley]

"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:3f2cbdfd$0$4191$afc38c87@news.optusnet.com.au...

"Eugene Rosenzweig" <ugn@hotmail.com


That is correct. A very common fault for these stations we find is the
switch starts getting stuck so the tip starts overheating.


** Weller WTCPNs become "gravity sensitive" first - then stick on.
That
is why I dumped mine and bought a Hakko 900M and station. Not one bug in 8
years of daily use with the SAME iron.

The tips last for years too.




.............. Phil


Borrowed from the net.

The curie effect switch in the solder pencil is very light and I have found
it to be a common failure item and
a very expensive part to replace. ( Aus$ 50 +) So much so that just two
weeks ago I hacked into my Weller station to add a little electronics to
help that switch reach a ripe old age instead of costing me money every 6
months or so.
The station I have has just a mains transformer with 24 volt AC output to
the soldering pencil which contains the curie temperature switch and
element.
The modification consisted of adding a triac, a 220 ohm resistor and a
small
heat sink (1 to 2 Sq. in) to the base unit and some wiring changes to the
solder pencil to bring the switched contact(s) into the base unit. It is
simple to
arrange things so that the switch now triggers the triac via the
220 ohm resistor and instead of switching 1.8 amps or so, it is in the
order of
a few milliamps. The triac I used is marked SC141D and appears to be a
common item.

Just a few GOTCHA's
I decline to give further details of this modification for the following
reasons:
1)The work involves opening and working on the base unit which has mains
wiring inside the unit. This can be very dangerous to some less experienced
technicians. YOU HAVE BEEN WARNED
2)The work involves some rewiring inside the solder pencil to use the
existing wiring in a slightly different way. It is essential to ensure the
integrity of the current earthing system. This is an IMPORTANT safety
matter. Ignore at your peril.
3)The work involves adding components in a safe and durable manner inside
the base unit.
A few minutes examination and some thought will show experienced
technicians
how to simply implement this idea. If you have to ask someone how to do it,
it is likely that you should NOT attempt the work. This is not a tease. It
is intended to ensure that no-one puts themself in any danger to save a few
dollars
4)The final GOTCHA. Don't start this work without making sure you have a
working soldering iron. It is rather disconcerting to reach for an iron
only to
realise it is in pieces before you. Silly? That is exactly what this old
coot did. Duhh-----

 

[Parmin]

"David Yates" <dyates1NOSPAM@bigpond.net.au> while reading the
NewsGroups, picked his nose and bring out
news:JA2Xa.7524$bo1.3124@news-server.bigpond.net.au:

Try Oatley Electronics . . This 12V kit will run on 9V and 6V, but
haven't tried it at lower voltages.
http://www.oatleyelectronics.com/kits/K191.html

Excellent output!

Dave

"Mike Buckler" <someone@someplace.com> wrote in message
news:2cnnivo6msrdep47qvd1ou06med4dlsk2p@4ax.com...

Does anyone know of any suppliers in Aus that deal in white LED
arrays
like this
one
http://www.theledlight.com/versalux.html

It has it's own built in DC to DC converter so that it can run from a
2.2
to
13.8 V supply.



Mike

Or even the Dicksmith kit k-3019 white LED torch where it use
a Maxim chip to step up the supply voltage.
Some Maxim power chip have wide range input voltages.
Now where are my specs??

With a little tinkering, you should be able to make something
similar to the versalux at a fraction of the price.
Base on the picture of the versalux unit, I think it use the
maxim chip too. I may be able to find a circuit for it..somewhere
in my pile of junk.


Hope this helps - Good luck

Par.

 

[Alan Rutlidge]

Thanks guys for taking the time to verify my assumptions re the Weller
soldering iron tips etc.
Appreciated.

Cheers,
Alan

 

[Louie]

Rob Judd wrote:

Louie,

Try reading it with a meter. If it's dead short both directions (as I
suspect it might be) then it's what they call a 0-ohm resistor. Used in
manufacuring to allow links to be inserted by machine.

that seems to be the consensus because it has 0 ohms in both directions.
but still i'm thinking it could be an inductor. looking on the bottom
side most of them have no intervening traces between thier solder
points, so why would they be there if they were just jumpers?

i don't have an ESR meter, so i can't tell if they're chokes or not. but
i don't know what else could they be.

louie

 

[Mike Harding]

On Wed, 6 Aug 2003 11:42:40 +1000, "jabboo"
<jabboo@(nospam)optusnet.com.au> wrote:

ive been working on this traffic light circuit in my spare time now
and have finished it and got it working with LED's

Good stuff How did you do the control? Hard logic or
a microprocessor?

now I want to be able to add relays so I can control 12v halogen lights

12V halogen lamps usually consume quite a lot of current,
1 or 2 amps at least.

the circuit runs off 5V
and when I measure the voltage coming out of the circuit which is going to
turn the relays on it reads between 2.3V and 3.3V

Where are you measuring that V and what component is
producing it?

my question is how can I get a relay to work on this ?

You can't really drive one directly but you could drive a
transistor which, in turn, could switch a realy.

another question could I use triacs ?
ive read some where that I cant because its DC voltage and that the triac
will switch them on but wont switch them off ?
is this true ?

Yes. The gate terminal is used to turn a triac or thyristor (also
know as SCR) _on_ but the only way to turn it off is when the
current flowing through the triac drops to virtually zero. This
feature makes them quite useful on AC systems where the
current passes through zero twice in each cycle.

You could probably use a transistor (perhaps a logic
level MOSFET) to drive the halogens but they will take
quite a bit of current - especially when they are cold, the
current is a lot higher for a short period then.

It might be better to put your efforts into a new project and
consider the traffic lights complete?

Mike Harding

 

[Ralph]

Have you looked at using an ULN2803. 8 drivers in one IC. Up to 1/2 amp
(total) I think.

--
remove n u m b e r s to reply
jabboo wrote in message <3f305d0b$0$15136$afc38c87@news.optusnet.com.au>...

ive been working on this traffic light circuit in my spare time now
and have finished it and got it working with LED's
now I want to be able to add relays so I can control 12v halogen lights

the circuit runs off 5V
and when I measure the voltage coming out of the circuit which is going to
turn the relays on it reads between 2.3V and 3.3V
my question is how can I get a relay to work on this ?
another question
could I use triacs ?
ive read some where that I cant because its DC voltage and that the triac
will switch them on but wont switch them off ?
is this true ?

--
Anthony Jabbour

 

[Steve]

Louie <beavisnbutthead@softhome.net> wrote in message news:<rvVXa.72382$Ho3.10591@sccrnsc03>...

Rob Judd wrote:

looking on the bottom
side most of them have no intervening traces between thier solder
points, so why would they be there if they were just jumpers?

Sometimes they'll put a 0 ohm jumper in place of a component that was
considered unnecessary (after testing) in the final product, rather
than doing the PCB over again.

Or, the PCB is designed for multiple versions of one product, and the
version with the jumper is "missing" a component that is used by the
more feature-filled variations.

 

[Louie]

Steve wrote:

Sometimes they'll put a 0 ohm jumper in place of a component that was
considered unnecessary (after testing) in the final product, rather
than doing the PCB over again.

Or, the PCB is designed for multiple versions of one product, and the
version with the jumper is "missing" a component that is used by the
more feature-filled variations.

hmmm.... i never thought about that. this is much more complicated than
i thought.

louie

 

[jabboo]

thanks mike

I went for a 555 timer connected to a 4017 decade counter
made the first 6 counts green
next count yellow
last 3 counts red
works pretty good
then set up 5 different resistors on a 5 way switch to control the speed of
the pulses
heres a picture
http://members.optusnet.com.au/jabboo/Picture-007.jpg
please disregard the messy wiring
I didn't have the tools to make a PCB
any ideas for the future?
one thing I would of done differently is not hard wire the 5 way switch...
instead I should of used some connectors so I could remove it.


--
Anthony Jabbour


"Mike Harding" <mike_harding1@hotmail.com> wrote in message
news:a4r0jv0iaep87k580tb74f6s10vafg1ucu@4ax.com...

On Wed, 6 Aug 2003 11:42:40 +1000, "jabboo"
jabboo@(nospam)optusnet.com.au> wrote:

ive been working on this traffic light circuit in my spare time now
and have finished it and got it working with LED's

Good stuff How did you do the control? Hard logic or
a microprocessor?

now I want to be able to add relays so I can control 12v halogen lights

12V halogen lamps usually consume quite a lot of current,
1 or 2 amps at least.

the circuit runs off 5V
and when I measure the voltage coming out of the circuit which is going
to
turn the relays on it reads between 2.3V and 3.3V

Where are you measuring that V and what component is
producing it?

my question is how can I get a relay to work on this ?

You can't really drive one directly but you could drive a
transistor which, in turn, could switch a realy.

another question could I use triacs ?
ive read some where that I cant because its DC voltage and that the triac
will switch them on but wont switch them off ?
is this true ?

Yes. The gate terminal is used to turn a triac or thyristor (also
know as SCR) _on_ but the only way to turn it off is when the
current flowing through the triac drops to virtually zero. This
feature makes them quite useful on AC systems where the
current passes through zero twice in each cycle.

You could probably use a transistor (perhaps a logic
level MOSFET) to drive the halogens but they will take
quite a bit of current - especially when they are cold, the
current is a lot higher for a short period then.

It might be better to put your efforts into a new project and
consider the traffic lights complete?

Mike Harding

 

[jabboo]

that's a brilliant idea
I even think I have one
they will accept 12v wont they ?

so I connect the output from the circuit into the uln2803
then the output from the 2803 into the relay
ill go try it

--
Anthony Jabbour


"Ralph" <Ralph.Smith2@team4.telstra6.com> wrote in message
news:bgprlv$dnk$1@mws-stat-syd.cdn.telstra.com.au...

Have you looked at using an ULN2803. 8 drivers in one IC. Up to 1/2 amp
(total) I think.

--
remove n u m b e r s to reply
jabboo wrote in message
3f305d0b$0$15136$afc38c87@news.optusnet.com.au>...
ive been working on this traffic light circuit in my spare time now
and have finished it and got it working with LED's
now I want to be able to add relays so I can control 12v halogen lights

the circuit runs off 5V
and when I measure the voltage coming out of the circuit which is going
to
turn the relays on it reads between 2.3V and 3.3V
my question is how can I get a relay to work on this ?
another question
could I use triacs ?
ive read some where that I cant because its DC voltage and that the triac
will switch them on but wont switch them off ?
is this true ?

--
Anthony Jabbour

 

[Phil Allison]

"Glenn Pure" <Glenn.Pure*delete_this_for_reply*@pcug.org.au> wrote in
message news:3f30e6da.1348616@newshost.pcug.org.au...

I am building a circuit using an LM335 temperature sensor (which is
just a temperature sensitive zener diode). However, I want it to
operate it so the output at ambient temperature is around 6 volts. The
normal voltage drop at 25 C across the LM335 is very close to 3 volts
so I need to find another 3 volts or so between ground and the LM335.

** Why not use two in series ???

I was hoping to use a 3.3 volt zener between the LM335 and ground

** Then the nice +10mV per K would be where compared to a window ??



but

it seems these 'power' zeners need quite a few milliamps running
through them before they will generate their rated voltage drop - more
current than is desirable to run through the LM335. (As you can see, I
don't have much experience with zeners). Is there a simple solution to
this (that doesn't involve a pile of normal diodes in series)? I
really want a passive device to solve this if at all possible, and one
that can simply sit in series with the LM335.

** If you feed the LM 335 from a (temp compensated ) current source any
resistor will give a fixed offset voltage.

Would a voltage divider created with two resistors in series (one on
each side of the LM335) do the trick provided I chose my resistor
values carefully?

** Huh ? Like two resistive body guards ??




............. Phil

 

[John Crighton]

On Wed, 06 Aug 2003 11:42:39 GMT,
Glenn.Pure*delete_this_for_reply*@pcug.org.au (Glenn Pure) wrote:

I am building a circuit using an LM335 temperature sensor (which is
just a temperature sensitive zener diode). However, I want it to
operate it so the output at ambient temperature is around 6 volts. The
normal voltage drop at 25 C across the LM335 is very close to 3 volts
so I need to find another 3 volts or so between ground and the LM335.

Hello Glenn,

how about using an operational amplifier with a gain of + 2,
to amplify the 3volts out of the LM335 to 6volts out from
say an LM358 or similar op amp.

http://www.national.com/ds/LM/LM158.pdf
look at page 11
Typical Single Supply Applications
Non inverting DC gain.

So for a gain of +2 make R1 and R2 both 10K
on the diagram shown on top of page 11.
Vin connects to your LM335 (3 volts)

You will also notice that National will give you
some free samples.

I love this internet, you can ask a question and
even get the parts for nothing.....heh heh heh....

Glenn, slight change of topic. How did your
welder modifications turn out?

Regards,
John Crighton
Hornsby

 

[Phil Allison]

"John Crighton" <john_c@tpg.com.au>

Hello Glenn,

how about using an operational amplifier with a gain of + 2,
to amplify the 3volts out of the LM335 to 6volts out from
say an LM358 or similar op amp.

" Is there a simple solution to this (that doesn't involve a pile of normal
diodes in series)? I
really want a passive device to solve this if at all possible, and one
that can simply sit in series with the LM335. "


** John - you snipped this - Glenn knows how to use an op-amp already.



.......... Phil

 

[John Crighton]

On Thu, 7 Aug 2003 10:38:58 +1000, "Phil Allison"
<philallison@optusnet.com.au> wrote:

"John Crighton" <john_c@tpg.com.au


Hello Glenn,

how about using an operational amplifier with a gain of + 2,
to amplify the 3volts out of the LM335 to 6volts out from
say an LM358 or similar op amp.


" Is there a simple solution to this (that doesn't involve a pile of normal
diodes in series)? I
really want a passive device to solve this if at all possible, and one
that can simply sit in series with the LM335. "


** John - you snipped this - Glenn knows how to use an op-amp already.



......... Phil

Hello Phil,
well, I guess I just got over excited, explaining the obvious,
that happens to us hobbyists occasionally.
CU
JC

 

[Phil Allison]

"Graham" <hurfy@alphalink.com.au> wrote in message
news:3f31c232$1@news.alphalink.com.au...

how hard would it be to design something for the phone ( landline of
course)
that, when it depicts that the callers number is blocked or whatever,
starts
a recording saying that calls with blocked numbers wont be answered...a
very
selective answring machine without the message taking facilities.....I
remember that some answering machines used to have different answers for
different callers a while back ...Would need to answer the call almost
straight away. Telemarketers dont have much time.
Would of course need to be a black box add on to the phone..

** I would love one of them myself.

The percentage of people who have blocked numbers is huge - most of
them do not realise their number is blocked or any idea how to unblock it
either. ( dial 1832 prior to the wanted number for a one time unblock )




............... Phil

 

[Mike Warren]

"Graham" <hurfy@alphalink.com.au> wrote in message
news:3f31c232$1@news.alphalink.com.au...

how hard would it be to design something for the phone ( landline of
course) that, when it depicts that the callers number is blocked or
whatever, starts a recording saying that calls with blocked numbers
wont be answered...a very selective answring machine without the
message taking facilities.

A bit too much for a one off device. Especially when it is illegal to
connect non-approved equipment to phone lines in Australia.

It could be done in software however, if you were willing to have
a computer always on. Still wouldn't be trivial and you would need
a caller ID compatible modem.

-Mike

 

[Rudolf Ladyzhenskii]

It really comes down to how many units you need.

Design can be done realtively easy, but anything connected to the phone line
must have approval. On top of that is manufacturing cost.
If you are talking single units, it is not worth the effort. If you are
after large quantities, contact me.

Rudolf


"Graham" <hurfy@alphalink.com.au> wrote in message
news:3f31c232$1@news.alphalink.com.au...

how hard would it be to design something for the phone ( landline of
course)
that, when it depicts that the callers number is blocked or whatever,
starts
a recording saying that calls with blocked numbers wont be answered...a
very
selective answring machine without the message taking facilities.....I
remember that some answering machines used to have different answers for
different callers a while back ...Would need to answer the call almost
straight away. Telemarketers dont have much time.
Would of course need to be a black box add on to the phone..


cheers

Graham
--

 

[Doug Laidlaw]

Graham wrote:

how hard would it be to design something for the phone ( landline of
course) that, when it depicts that the callers number is blocked or
whatever, starts a recording saying that calls with blocked numbers wont
be answered...a very selective answring machine without the message taking
facilities.....I remember that some answering machines used to have
different answers for different callers a while back ...Would need to
answer the call almost straight away. Telemarketers dont have much time.
Would of course need to be a black box add on to the phone..


cheers

Graham
--
Do you mean that the caller's number comes up as "Private" on your number

display? There seem to be plenty of devices in the U.S. that just ignore
these calls. In my experience however, a small percentage are important
calls you would want to take. It is worth taking the others to get these.

Doug VK3KDI.
--
Registered Linux user No. 277548.
Linux: in a world without fences, who needs Gates?

 

[Brian Goldsmith]

"Doug Laidlaw" <laidlaws@myaccess.com.au> wrote

Do you mean that the caller's number comes up as "Private" on your number
display?

There seem to be plenty of devices in the U.S. that just ignore
these calls.

*** Doug,not too sure by what this last sentence means,could you elaborate.
Thanks,Brian Goldsmith.

 

[David L. Jones]

On Thu, 07 Aug 2003 08:35:29 GMT, tronnort_@yahoo.com (David L. Jones)
wrote:

On Wed, 06 Aug 2003 11:42:39 GMT,
Glenn.Pure*delete_this_for_reply*@pcug.org.au (Glenn Pure) wrote:
I am building a circuit using an LM335 temperature sensor (which is
just a temperature sensitive zener diode). However, I want it to
operate it so the output at ambient temperature is around 6 volts. The
normal voltage drop at 25 C across the LM335 is very close to 3 volts
so I need to find another 3 volts or so between ground and the LM335.

I was hoping to use a 3.3 volt zener between the LM335 and ground but
it seems these 'power' zeners need quite a few milliamps running
through them before they will generate their rated voltage drop - more
current than is desirable to run through the LM335. (As you can see, I
don't have much experience with zeners). Is there a simple solution to
this (that doesn't involve a pile of normal diodes in series)? I
really want a passive device to solve this if at all possible, and one
that can simply sit in series with the LM335.

Would a voltage divider created with two resistors in series (one on
each side of the LM335) do the trick provided I chose my resistor
values carefully?

Cheers
Glenn

Hi Glenn,
How about using a 3V reference diode in series?
Farnell have an LM4120 available, tempco is 50ppm.

If I remember rightly, the LM4120 is an unstable beast needing a
fairly specific bypass cap value. Beware. The data sheet should have
all the details.

Might be a 4 component solution then:
Resistor
LM335
LM4120 + cap

Lots of other (more stable) voltage reference devices are available
that don't need a bypass cap, but not in 3V from Farnell. 2.5V good
enough?, there are a zillion of those.

Regards
Dave
---------------------------
(remove the "_" from my email address to reply)