Chip with simple program for Toy

[Kevin Aylward]

N. Thornton wrote:

"Patrick Leonard" <transactoid@rogers.com> wrote in
news:iHtNa.58918$a51.44869@news02.bloor.is.net.cable.rogers.com:

I'm trying to figure out if its possible to build a super simple
signal generator uisng only one transistor and no other ICs.

The idea being you charge up a capacitor through a resistor then
when the cap is at an adequate potential, its voltage will turn on a
transistor. The transistor being on simply completes a circuit
allowing the cap to discharge. Whence the cap has discharged, the
transistor turns off, and the cap charges again. Repeat......

This seems logical to me, yet I cannot design a circuit that works
this way....it always seems like I'm missing something. Am I just
not being "clever" enough, or is such a circuit indeed impossible?


Hi Patrick.

This is perfectly possilbe, I'm surprised so many have queued up to
say it isnt.

Ah, I was going to ascii it, but I've got proportional font on.
Basically you put transistor (C and E only) in parallel with your Cap,
and add the R in series with that lot. Voila, one oscillator.

Or you can use a neon at higher Vs, and it looks nice.

I already gave that solution a few days ago. They may be reliability
issues with this method.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[roma]

roma <roma@shaw.ca> wrote in news:Xns93AFD34C18619ewbod25@
24.69.255.211:

"Patrick Leonard" <transactoid@rogers.com> wrote in
news:iHtNa.58918$a51.44869@news02.bloor.is.net.cable.rogers.com:

I'm trying to figure out if its possible to build a super simple
signal generator uisng only one transistor and no other ICs.

The idea being you charge up a capacitor through a resistor then
when
the cap is at an adequate potential, its voltage will turn on a
transistor. The transistor being on simply completes a circuit
allowing the cap to discharge. Whence the cap has discharged, the
transistor turns off, and the cap charges again. Repeat......

This seems logical to me, yet I cannot design a circuit that works
this way....it always seems like I'm missing something. Am I just
not
being "clever" enough, or is such a circuit indeed impossible?

Thanks
Patrick




See cheapo oscillator page 23 http://members.shaw.ca/roma
roma

Further to my last posting about cheapo oscillator .
I had this little circuit for over 30 years and in my time of learning
about transistors I fooled around with it to find out more about "
Negative resistance region of a reversed-bias silicon transistor "
which can be used as a relaxation oscillator , which is similar to a
UJT .
The frequency is coverned by the time constant RC , the power supply
and the size of the negative-resistance region which also governs the
signal amplitute . It will drive a 100 ohms earpiece as a buzzer .
Roma

 

[N. Thornton]

"Kevin Aylward" <kevin@anasoft.co.uk> wrote in message news:<g8OOa.11757$4O4.1182246@newsfep2-win.server.ntli.net>...

N. Thornton wrote:
"Patrick Leonard" <transactoid@rogers.com> wrote in
news:iHtNa.58918$a51.44869@news02.bloor.is.net.cable.rogers.com:

I'm trying to figure out if its possible to build a super simple
signal generator uisng only one transistor and no other ICs.

This is perfectly possilbe, I'm surprised so many have queued up to
say it isnt.

Ah, I was going to ascii it, but I've got proportional font on.
Basically you put transistor (C and E only) in parallel with your Cap,
and add the R in series with that lot. Voila, one oscillator.

Or you can use a neon at higher Vs, and it looks nice.

I already gave that solution a few days ago.

Yup, yet folks were still saying it couldnt be done. Sometimes its
good to act as 'backup', for want of a better word.

They may be reliability
issues with this method.

Anyone know about this for definite? I know the trs wont normally come
specced to operate like this, but are there many failures in practice?

Regards, NT

 

[Charles Jean]

Answer depends on what the question is.
So far, so good. Ideally, system is now at 100 degree C and starting
to boil, 1594 seconds after closing the switch. This could be be the
answer to the question "How long does it take to START to boil 500ml.
of water." The heat of vaporization of water is 540 calories/gm, so
to completely convert(ideal conditions, atmospheric pressure) 500 gm
of water at 100 deg C to 500 gm of steam at 100 deg C is going to take
an additional
(500 gm)(540 cal/gm) = 270000 cal
or
(270000 cal)(4.18 Joules/cal) = 1128600 Joules
or
(1128600 Joules)/(98.6 Joules/sec) = 11446 seconds

to "boil the water(away)".

Anyway, my microwave's got this rig beat all to Hell.....


On Sun, 6 Jul 2003 16:02:00 -0700, "Howard Henry Schlunder"
<howard_hs@yahoo.com> wrote:

"JohanWagener" wrote in message news:be9kvh$1c3$1@ctb-nnrp2.saix.net...
Please comment on my calculations

Ok.

If I take two 10W resistors of 1k each and put them in parallel I would
get
a 500ohm resistor right?

Yes. The combination will be designed to dissipate 20W as well. Submerged
in water, however, it probably still last a long time.

Now if I apply 220V over it there would be about
0.44A flowing through it. That is power of about 98.6W.

Yes and yes.

How long will it take to boil 500ml of water?

Assuming the water starts at 25 degrees Celcius, you are at 1 atmosphere of
pressure, and no energy will get lost to the surrounding air/containers/or
otherwise, it will take:

(100Degrees - 25Degrees)*(500cm^3)*(4.19Jewels/Degree/cm^3)/(98.6
Jewels/Second) = 1594 Seconds.

Note that this is the time it will take to reach boiling point. The heat of
vaporization of water is way higher than it's specific heat in the liquid
phase. Therefore, if by "boil" you mean, "completely boil away" my
calculation would be an extreme underestimate. Unfortunately, I don't
remeber the heat of vaporization right off hand, so I can't provide you with
any calculations there.

Howard Henry Schlunder




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If God hadn't intended us to eat animals,
He wouldn't have made them out of MEAT! - John Cleese

 

[Winfield Hill]

John wrote...

I've seen regular zeners oscillate with an r-c, but usually
erratically and at much lower currents.

Does anybody know what's really going on here?

It's well understood. The subject was worked nearly
to death on s.e.d. a few years back, and Tony Williams,
Bill Sloman, myself and a few others spent altogether
too much time on it.

Use Google and search on zener oscillation.

Thanks,
- Win

 

[Jhon Smith]

richardgrise@yahoo.com (Rich Grise) wrote in message news:<3df9fd6c.0307091822.7d7508c3@posting.google.com>...

temp_trash666@yahoo.com (Jhon Smith) wrote in message news:<6899029c.0307090520.7d6619c1@posting.google.com>...
Hello,

I would like to have information about the projectors used in
"projector alarm clock" (clocks that project the time on the wall or
ceiling. see http://www.google.com/search?q=%22+Projection+Alarm+Clock%22
for examples).

Specifically, I would like to know:


- The technology used. I read somewhere that LED's are used, but it
seem unrealistic due to LED's beam width.

- Is it possible to buy a projector (that you can control yourself) ?

I really want to project other things then alphanumeric characters,
but with about the same precision and number of elements. So if buying
a customized projector is not possible, I plan making one myself (if
this is technically feasible).

Thank you if you can provide any information on these subjects.

John

A http://www.google.com search on 'lcd overhead projector' (no quotes)
yielded this, amongst others:
http://www.audiovisualizers.com/madlab/lcd_proj.htm

Good Luck!
Rich

Thanks. I had a quick look and it seem very interesting, but overkill
for what I want to do.
I am really looking for something very cheap, but with can have *very*
low resolution (I mean 5 X 5 or 10 X 10 is already ok for the
application I have in mind), and monochrome is ok. (That's why I
think the technology used in alarm clock projectors could be adapted
for my need)
Ideally I want to control each pixel individually, like having one
pixel refresh at 60Hz, and other one at 70Hz and so on.

I'll continue searching...

Thanks,

John

 

[petrus bitbyter]

"Henry Kolesnik" <wd5jfr@oklahoma.net> schreef in bericht
news:vg9hkh9moa449@corp.supernews.com...

If you've received a private reply please share it as I also recall the
test
you've mentioned.
tnx
hank wd5jfr
scottatlgh@despammed.com> wrote in message
news:3e03c610.0306260931.6a6d0b93@posting.google.com...
About twenty-five years ago a colleague showed me how to do a ring
test on a power transformer. I need to test a SMPS transformer now and
I can't remember how he did this test. I know he used an oscilloscope
to look at the ringing but that's as far as my memory serves me. A
website on the internet explained some kind of a ring test but it
didn't give me the output I was expecting. Can someone please point me
in the right direction.

Thanks,

Scott

Scott,

You can find all you need in:

http://www.repairfaq.org/sam/flytest.htm

pieter

 

[Keith R. Williams]

In article <be9igt$t9c$1@ctb-nnrp2.saix.net>,
rebeldog@webmail.co.za says...

HAHAHAHA BOOOOM! HAHAHA

Humor was indeed my intent. However, why do you suppose that
refinerys, and such, have flares burning 24/7? Burning off the
bad stuff is far better than letting it accumulate.

--
Keith

"Keith R. Williams" <krw@attglobal.net> wrote in message
news:MPG.19720e123aee345498a51e@enews.newsguy.com...
In article <be9eij$rfc$1@ctb-nnrp2.saix.net>,
rebeldog@webmail.co.za says...
You mean electrolysis? I don't want the H and O and Cl that might be
formed
but thanks anyway. I also thought about that one.

Light a match.

--
Keith

 

[Tim Shoppa]

temp_trash666@yahoo.com (Jhon Smith) wrote in message news:<6899029c.0307090520.7d6619c1@posting.google.com>...

Hello,

I would like to have information about the projectors used in
"projector alarm clock" (clocks that project the time on the wall or
ceiling. see http://www.google.com/search?q=%22+Projection+Alarm+Clock%22
for examples).

Specifically, I would like to know:


- The technology used. I read somewhere that LED's are used, but it
seem unrealistic due to LED's beam width.

I think that they are LCD screens with a light source behind and optics
in front. With a point-like light source you may not need optics in front.

- Is it possible to buy a projector (that you can control yourself) ?

Yeah, just buy some "transflective" LCD's and some lenses. Digikey
(http://www.digikey.com/) sells LCD's and Edmumd Optics
(http://www.edmundoptics.com) and Anchor Optical
(http://www.anchoroptical.com) sell industrial and surplus lenses.

I really want to project other things then alphanumeric characters,
but with about the same precision and number of elements. So if buying
a customized projector is not possible, I plan making one myself (if
this is technically feasible).

Making your own LCD glass is probably feasible... but it sounds like
a big project.

If you just want a big display that you can form all the segments yourself
on, think about buying those electroluminescent sheets and cutting them
to your desired shapes. This way you avoid the optics, and the economic
factors are favorable for displays of a few feet in size.

Another projector technology involves individual mirrors that can be
swung around to turn them "off", sort-of like those electromechanical
dot-matrix displays you used to see in airports and train stations.

Tim.

 

[the Wiz]

How about a kit or semi-kit?

4 channel
http://www.mpja.com/productview.asp?product=8480+KT

2 channel
http://www.mpja.com/productview.asp?product=8480+KT



i141802596@yahoo.com (nick) wrote:

1.if i want to make a simple remote controller and reveiver ,e.g. when
i pressing button A from the controller,then LED A will turn on in the
receiver side,i don't want the use IR TX &RX,so i want to use RF, but
i have no idea to make it,so anyone can give me a simple diagram,or
give me some web sites about the RF.

2.i have found some diagrams about them ,i think they are very
complex for me ,in the diagrams a component called inductor,what is
this? , How to use it?

3.if i want to make a simple bug,is it principle like the remote
contoller? i have found some web sites only teach how to make the
transmitter,they use radio to work as the receiver, that means anyone
turn their radio to the same band ,then they also can receive the
singles?

More about me: http://thelabwiz.home.mindspring.com/
VB3 source code: http://thelabwiz.home.mindspring.com/vbsource.html
VB6 source code: http://thelabwiz.home.mindspring.com/vb6source.html
VB6 - MySQL how to: http://thelabwiz.home.mindspring.com/mysql.html
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter atat mindspring dotdot com. Fix the obvious to reply by email.

 

[Lord Garth]

"baywood" <baywood@drizzle.invalid.com> wrote in message
news:jlcPP5CEpj1f8JKuo2sBx65HQeuw@4ax.com...

What I have been looking for is a circuit for a switch that operates
at a set relative humidity. Essentially I need a 5% RH range with one
fan turning on at the low end and another at the high end of the
range. I'll be working with 12VDC and the fans draw 130mA each. My
knowledge of electronics is pretty limited. It seems most RH sensors
are based on capacitance (e.g.
http://www.kollar.com/observatory/cloud2/691901.pdf) and I have no
idea of how to build a switch based on capacitance. Anything pointing
me in the right direction would be appreciated.

The sensor you link to is not capable of a 5% RH reading. The spec sheet
says 10% to 90%.

One way to accomplish the switch is to put the sensor into an oscillator
circuit. As the RH changes, so does the output frequency or the pulse
width.
You can either detect the pulse width or frequency that represents the 5%
RH.

You will also need to design in some hysteresis to prevent the jitter about
the trigger point.

 

[Mark Haase]

In article <4f981f90.0307081633.16eb9fe3@posting.google.com>,
i141802596@yahoo.com (nick) wrote:

how to use it and it is used to...?
who can show me the picture of it?

thanks

I'm no expert, but I think my newbie perspective might be easier for you
to understand.

This is where I did my learning:
http://www.ibiblio.org/obp/electricCircuits/DC/DC_15.html

Its a great site.

Basically, an inductor is a coil of wire which generates a significant
magnetic field. If you have a powered circuit with a switch and
inductor, and multimeter watching it, when you close the switch, the
flow of electricity generates a magnetic field in the inductor, which in
turn generates a potential in the opposite direction of the power
supply. The effect is that the voltage in the circuit takes time to
"ramp up" to full value.

--
|\/| /-| |2 |<
mehaase at sas dot upenn dot edu

 

[John Popelish]

Mark Haase wrote:

In article <4f981f90.0307081633.16eb9fe3@posting.google.com>,
i141802596@yahoo.com (nick) wrote:

how to use it and it is used to...?
who can show me the picture of it?

thanks

I'm no expert, but I think my newbie perspective might be easier for you
to understand.

This is where I did my learning:
http://www.ibiblio.org/obp/electricCircuits/DC/DC_15.html

Its a great site.

Basically, an inductor is a coil of wire which generates a significant
magnetic field. If you have a powered circuit with a switch and
inductor, and multimeter watching it, when you close the switch, the
flow of electricity generates a magnetic field in the inductor, which in
turn generates a potential in the opposite direction of the power
supply. The effect is that the voltage in the circuit takes time to
"ramp up" to full value.

You still need work on some of the details. Yes, the current creates
the magnetic field, but the voltage drop across the inductor is
proportional to the rate of change of the current, not the magnitude
of the current. So your last sentence should replace "voltage" with
"current". It is the ramp up of current (a constant rate of change)
that produces an inductive EMF that bucks the applied voltage.
Without this effect, the inductor would be just a wire wound resistor.

--
John Popelish

 

[Baphomet]

Probably the easiest, although certainly not the most elegant, way would
be to put a 3.9volt zener diode between your 12 volt source and your desired
8 volt output. I don't have a part number off hand but it would have to be
at least a 24 watt job with a hefty heat sink or a higher wattage unit that
would require a more modest heat sink.

"Melaniegree64694" <melaniegree64694@aol.com> wrote in message
news:20030712062839.03232.00000203@mb-m12.aol.com...

Hi
Does anyone have a circuit to drop 12V DC to 8V DC with an output of 3
Amps?

Mel

 

[Baphomet]

Duh...change 24 watt to 12 watt. My multiplication chip is a bit rusty.

"Baphomet" <fandanospam@catskill.net> wrote in message
news:vh0jj3c3nqol49@corp.supernews.com...

Probably the easiest, although certainly not the most elegant, way
would
be to put a 3.9volt zener diode between your 12 volt source and your
desired
8 volt output. I don't have a part number off hand but it would have to be
at least a 24 watt job with a hefty heat sink or a higher wattage unit
that
would require a more modest heat sink.

"Melaniegree64694" <melaniegree64694@aol.com> wrote in message
news:20030712062839.03232.00000203@mb-m12.aol.com...
Hi
Does anyone have a circuit to drop 12V DC to 8V DC with an output of 3
Amps?

Mel

 

[Jonathan Kirwan]

On 12 Jul 2003 10:28:39 GMT, melaniegree64694@aol.com
(Melaniegree64694) wrote:

Does anyone have a circuit to drop 12V DC to 8V DC with an output of 3 Amps?

Hi, again.

This is just about taken from the data sheet for the LM317:

: ,-------------------c e-------,
: | Q2 \ / |
: | 2N3055 --- |
: | or MJE3055 | |
: | | R6 |
: +---------e c------+---/\/\---+
: | Q1 \ / 470 |
: | 2N2905 --- |
: | | |
: | / R4 |
: | \ 5K |
: | / |
: | R3 |inp,-------,out | 1N4002
: +12V or >---+-+---/\/\---+---| LM317 |---+----+--+------+-------+---> 8V
: more | 22 '-------' | | | |
: | adj| / --- | |
: | | \ R1 / \ D1 | |
: | | / 270 --- + | |
: --- C1 | | | --- C2 / R5
: --- 10uF +-------+---+---' --- 47uF \ 1500
: | | + | - | /
: | \ R2 --- C3 | |
: --- / 1500 --- 10uF | |
: gnd \ - | --- ---
: | | gnd gnd
: --- ---
: gnd gnd


I think the output voltage might be a tenth of a volt or so
above your desired 8V, but very close.

If you want to try something just a little bit easier, here's a
modified version without Q2 and R6:

: +---------e c-----------------,
: | Q1 \ / |
: | 2N2955 --- |
: | or | |
: | MJE2955 / R4 |
: | \ 10 |
: | / |
: | R3 |inp,-------,out | 1N4002
: +12V or >---+-+---/\/\---+---| LM317 |---+----+--+------+-------+---> 8V
: more | 1.5 '-------' | | | |
: | adj| / --- | |
: | | \ R1 / \ D1 | |
: | | / 270 --- + | |
: --- C1 | | | --- C2 / R5
: --- 10uF +-------+---+---' --- 47uF \ 1500
: | | + | - | /
: | \ R2 --- C3 | |
: --- / 1500 --- 10uF | |
: gnd \ - | --- ---
: | | gnd gnd
: --- ---
: gnd gnd


I think that should work okay, as well. You'll should use some
heat sinks on the 2N2955/2N3055/LM317 type parts, just to be
safe. The LM317 is some US$0.60 at Digikey. I don't know what
Farnell charges, but you can look there and see.

While I haven't built these to test them, I believe they may
work as specified. If it turns out that you need to support an
input voltage a little below 12V, you can adjust R3 to 1 ohm and
that will buy you back a few more tenths on the input side.

Jon

 

[Garrett Mace]

"Day Vee" <my_newsgroups@btinternet.com> wrote in message
news:jbt0hvo1c4m1ilhmqog3rr103dvgg1phid@4ax.com...

Try this:
Put your mobile/cell phone in an all metal biscuit/cookie tin/box.
Call it from another phone and it responds.
In theory this should not happen.
Whatever became of Micheal Faraday's "cage principle" ?

There's summat strange going on ...

Day Vee

Not really, for most people the phone won't in fact respond, unless (like
you) they have a cell tower on their roof.

 

[Neil]

Is the tin earthed? or is it just acting like a bit of metal going up and
down in voltage (?) with the signal?

"Day Vee" <my_newsgroups@btinternet.com> wrote in message
news:8v11hvsu61cr5191t98370pjtek3pv6bkh@4ax.com...

On Sat, 12 Jul 2003 16:46:34 -0500, "Garrett Mace"
g.ryan@macetech.com> wrote:


"Day Vee" <my_newsgroups@btinternet.com> wrote in message
news:jbt0hvo1c4m1ilhmqog3rr103dvgg1phid@4ax.com...
Try this:
Put your mobile/cell phone in an all metal biscuit/cookie tin/box.
Call it from another phone and it responds.
In theory this should not happen.
Whatever became of Micheal Faraday's "cage principle" ?

There's summat strange going on ...

Day Vee


Not really, for most people the phone won't in fact respond, unless (like
you) they have a cell tower on their roof.

When you say "for most people", have you previously conducted a poll ?
Do the experiment and tell us YOUR result.
My nearest relay is about half a mile away.

 

[John Larkin]

On Sat, 12 Jul 2003 22:35:30 +0000 (UTC), Day Vee
<my_newsgroups@btinternet.com> wrote:

On Sat, 12 Jul 2003 16:46:34 -0500, "Garrett Mace"
g.ryan@macetech.com> wrote:


"Day Vee" <my_newsgroups@btinternet.com> wrote in message
news:jbt0hvo1c4m1ilhmqog3rr103dvgg1phid@4ax.com...
Try this:
Put your mobile/cell phone in an all metal biscuit/cookie tin/box.
Call it from another phone and it responds.
In theory this should not happen.
Whatever became of Micheal Faraday's "cage principle" ?

There's summat strange going on ...

Day Vee


Not really, for most people the phone won't in fact respond, unless (like
you) they have a cell tower on their roof.

Even if the cell tower were on my roof, I thaught a "Faraday cage"
composed of solid metal would stop ALL radiation, regardless of
strength.

It would be solid metal if you soldered or welded all the seams shut.
A cookie tin lid doesn't make a very good electrical contact to the
box. Really tight EMI shielded boxes have elaborate spring finger
stock or metallic gaskets around the seams. RF is sneaky stuff.

John

 

[Gareth]

Day Vee wrote:

Try this:
Put your mobile/cell phone in an all metal biscuit/cookie tin/box.
Call it from another phone and it responds.
In theory this should not happen.
Whatever became of Micheal Faraday's "cage principle" ?

There's summat strange going on ...

Day Vee

Only a perfect conductor will completely block all radiowaves. For a
non-perfect conductor the radiowave is attenuated exponentially as it
travels though the material. For most metals this attenuation is very
rapid and assuming that the signal is perfectly blocked is not far off.
However if you have a very thin bit of metal which is not a
particularly good conductor, and a strong enough signal to start with, a
detectable signal will get through.

I expect the cookie tin is made of very thin steel (steel not being a
particularly good conductor) so just enough signal gets through to make
the phone ring.

The skin depth of steel is about 0.05 mm at 1 GHz, so the signal will be
attenuated by a factor of:

e^(thickness/0.05)

so if your tin is 1/10 mm thick the signal will only be attenuated by

e^(0.1/0.05) = e^2 = 7.4

This is not a lot of attenuation and I am not surprised that a phone
could still work.

Try the experiment again with different metal containers. For example
if you have a good quality heavy saucepan with a metal lid try that.

Gareth.

PS I tried it and the signal was blocked.

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