Chip with simple program for Toy

[Mikal Hodvik]

I'm no expert on this, but I'm under the impression that it's primarily LOW
INERTIA that distinguishes a servomotor from the ordinary.

Cheers,
Mikal Hodvik


<DCServoMotor> wrote in message
news:416cab1d$0$26323$afc38c87@news.optusnet.com.au...

What is the difference between a brush type "ordinary" DC motor and DC
"servo" motor?
Does adding a quadrature encoder to the ordinary DC motor convert it to a
DC sevo motor?

 

[John Popelish]

Mikal Hodvik wrote:

I'm no expert on this, but I'm under the impression that it's primarily LOW
INERTIA that distinguishes a servomotor from the ordinary.

Short mechanical and inductive time constants and high peak torques
(demagnetization resistance) are what justify big bucks for high
performance servo motors. But there are lots of servo applications
that have little use for such prima donnas.

--
John Popelish

 

[Dr Engelbert Buxbaum]

anonymous wrote:

WARNING - dumb question follows - WARNING

consider yourself warned.

So I have a nice transformer that puts out 25V and 1.5A. I want to step it
down to 9V with some voltage regulators. The regulators say they are rated
for 1A and 37V max (given proper heat sinking).

If the output of the regulator is drawing < 100mA - do I have to worry about
the remaining output from the transformer?

A 25 V AC transformer after rectification will give 25 V x sqrt(2) = 36
V DC, which is marginal for your regulator.

The output of your regulator is 9 V, the device is drawing 100 mA at
this voltage. That is, your regulator converts (36 - 9)V x 100 mA = 2.7
W of electrical power into heat. This will require a heat sink to avoid
frying the regulator.

For both reasons I would either use a transformer with lower output
voltage (say, 12 V), or a switching regulator.

 

[CFoley1064]

Subject: Newbie in need of Science Fair Help...Please
From: "Gill" gkgill@adelphiaschmelphia.net
Date: 10/13/2004 12:26 PM Central Daylight Time
Message-id: <xJSdnYetd-6t-PDcRVn-rA@adelphia.com

Hi, I'm hoping someone out there can help me. I have a seventh grade son
who must do a Science Fair project. He has chosen to do a project based on
"Alternative Energy". His goal is to power his GameBoy using some form of
power other than batteries or electricity. Any and all alternative energy
sources are being considered.

The problem is that we have been unable to find any information that will
help us to achieve his goal. We have been to the library a number of times;
we have checked the book store; stopped in at Radio Shack; and have surfed
the Internet - all without luck. We are able to find books and websites
about Alternative Energy but they all just tell about what other energy
sources are out there (water, solar, static, etc.) but not information on
how to harness that energy and convert it to power for a particular device.

I have read article refering to a man who converted his TV to be powered by
in kids pedaling a bicycle but I can't find a "how to" for that either.
We've all seen the in Science books about powering a digital clock or
flashlight battery with a potato or lemon...could a series of potatoes
supply the 3 volts needed? We have tossed around a number of possible
approaches, including: potatoes; bicycle power; solar power; hand crank;
possible incorporation of a car alternator; and many more.

Any information on where to find instuctions for harnessing and converting
alternative energy (or any other insight you might have) would be very much
appreciated.

Thank you,

Renee

Hi, Renee. Glad to help.

First of all, voice of experience. Don't use the Nintendo -- it's too
expensive. You don't want to put anything in your kid's science project that
you can't afford to risk by smoking, losing, or having stolen. The Game Boy
qualifies on all three counts, especially the last. In addition, Game Boys
require a two part adapter -- one part replaces the battery, and the second is
the AC adapter. You'll have to buy one of those to get to the point that you
can apply power. Looks like too big of an investment. Go to Wal-Mart and get
one of those $10.00 LCD screen handheld games instead. Make sure they've got a
few in stock so you can buy two. But before you do, determine what kind of
alternative power you want to do, and how many batteries you're trying to
replace. Most of these handheld games require two (3V), 3 (4.5V), or 4 (6V) AA
batteries. By the way, it also might help while you're at Wal-Mart to get one
of those cheapie $10.00 digital voltmeters. You'll need it for the project,
because it will help you to get data (necessary for an A in any 7th grade
science project) as well as providing a check on your power sources before you
plug anything in. Remember, connecting power backwards with any of these
things usually means you let the smoke out.

The lemon idea with pennies and zinc mail is interesting. You're creating a
battery cell with a potential of about 0.9V. The problem is, the cell is only
capable of providing a couple of mA before it bogs down. Most of that has to
do with the surface area of copper and zinc which comes in contact with the
acetic acid of the battery. Let's say you've got 3 lemons in series, which
would make a 2.7V battery. You would then choose a two battery handheld LCD
game, connect your batteries together with small alligator clips, and hook your
lemons battery up to the + and - battery clips inside the game with the free
ends of the test leads (view in fixed font or M$ Notepad):


.---------------------------.
| Game |
| Connect Lemons to Battery |
| Clips Using Gator Clips |
| |
| + - |
'-----o---------------o-----'
| |
| |
.-----' '--------.
| |
| |
| .-. .-. .-. |
'-----( L )--( L )--( L )------'
'-' '-' '-'
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

If the battery bogs down, you might have a problem. One way to solve it is to
put a couple of 3-lemon battery strings in parallel. Make sure you've got the
polarity straight.

Another option would be a bike generator. You can get these inexpensively from
many sources. One good source is the retired guy down the street who fixes up
and sells used bikes as a hobby. He's probably got a couple of these
generators in his junkbox, and will be willing to part with them for a couple
of bucks and a six of his favorite malt libation. If you've got an exercise
bike lurking around, you can hook up the bike generator to provide a power
source. You may come up with another way to crank the generator besides
spinning on a bike tire sidewall, but that's up to you. Bicycle generators
usually put out AC (alternating current). They will typically produce 6 Volts
AC at up to 1/2 Amp. You won't need anywhere near that much current, so you're
OK there. What you will need is a way to rectify that power, and regulate it
so it has a steady voltage like a battery. This is one which is particularly
good for a 6V toy (4 AA batteries) or 4.5V (3 AA batteries). In order to get
safe DC power from the generator AC, you will need something like this (view in
fixed font or M$ Notepad):

.-----------.
| | ____
| | D | | +
| o-----o--->|---o---------o--|7806|--o--o
| Bike | | | | |____| |
| Generator | | D | | | |
| | '---|<-----. +| | +|
| | | | --- | --- 6 Volts
| | D | | --- | ---
| | .--->|---' | C1| | C2|
| o-----o | | | |
| | | D | | | |
| | '---|<-----o-------o----o-----o--o
'-----------' -

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

The 6 VAC is retified by the 4 diodes labelled D. Charge is stored on
capacitor C1 such that the DC voltage input to the voltage regulator will be
near the peak DC produced by the generator (about 9VDC). The 7806 voltage
regulator drops and smooths out the voltage to 6VDC, with cap C2 required to
ensure stability of the regulator. I would choose 1N5819 diodes for D, a
1000uF 25V cap for C1, and a 10uF 25V cap for C2. All of these, along with the
7806 regulator and perfboard to put the components on, are available from
Mouser.com or Radio Shack. E-mail me if you need help getting the components
together. Please put "Science Project" in the heading, or it will get sent to
dev.null.

The above circuit is good for a 4 battery device. If you want a 3 battery
device, choose a 7805 regulator in place of the 7806. That will give you 5VDC,
which is close enough to 4.5V for what we're doing here.

A third option is solar power. Radio Shack has a 6V 50mA solar panel for $16
USD which will fill the bill perfectly for a 4-battery device. You just hook
up the red wire to the + and the black wire to the - battery terminals on the
battery clips of the toy. Simple and straightforward.

For your project, you might want to try to find a 3V toy and go with the lemon
battery, as well as the 6V toy and go with the generator and rectifier/voltage
regulator. I'm not sure what kind of data you can get from the solar cell
that's useful in a science project. Remember, by 7th grade they're supposed to
be able to do a paper with hypthesis, data, and writeup. With a cheapie
voltmeter you will be able to get voltage readings, and you might be able to
get something of a DC current reading, too. That will be enough for what you
need.

When doing these things, it's really good to teach the First Axiom Of
Engineering Projects, taught to me by a wise engineer years ago:

*** HURRY EARLY ***

Hopefully this isn't due tomorrow next week (unfortunately, that was the case
with both of my kids). Deciding what to do and getting the components together
is a good first step, and should be done as soon as possible.

Good luck
Chris

 

[John Larkin]

On Thu, 14 Oct 2004 22:33:03 -0700, "john jardine"
<john@jjdesigns.fsnet.co.uk> wrote:

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:6anrm0h3etrm722a523g21hlvlfgjffu8l@4ax.com...
On 11 Oct 2004 16:11:16 -0700, alanh_27@yahoo.com (Alan Horowitz)
wrote:

when a current just starts flowing into a RL or RC circuit, how does
the voltage "know" that it should be increasing exactly 63% during
each time-constant period?

And whence the number 63%?


How about this:

Charge a 1 farad capacitor to 1 volt and slap a 1 ohm resistor across
it. The resistor current is 1 amp, so the cap discharges, and the
voltage is at first declining at a rate of 1 volt per second. But
1/100 of a second later, the voltage is 0.99 volts, so the current is
only 0.99 amps, so the rate of discharge is only 0.99 volts per
second.

So we write a Basic program:

v = 1 ' charge the cap

for t = 1 to 100 ' then, for 1 second at 0.01 sec steps,

v = v - 0.01 * v ' discharge the cap by 1%

next

print v ' voltage is this, 1 second later


which simulates what I was doing above, but for a full second. The
value of v at the end is 0.36603 volts. That's close to 1/e, not exact
because I took 100 discrete steps, as an approximation to
continuous-time math. With 1000 steps, simulating 1 second of
discharge in 1 millisecond steps, you get 0.367700, even closer.

'e' is just nature's answer to a natural discharge curve.

John


Egads!. You've just given away the secret of Spice Transient Analysis. The
programmers will be calling for you with torches ablaze.

Hell, the average programmer couldn't set himself on fire.

Why is it that if anyone wants to *clearly* explain an algorithm or
sequential idea, they'll use "Basic" or a very Basic looking 'Pseudo-code',
yet most programmes seem written in "C".
It just isn't logical.
regards
john

Actually, I've done a lot of pll and control system simulation in
Basic. I really began using an HP 9100 desktop calculator (for
steamship throttle control system simulation), graduated to FOCAL,
then RSTS/E Basic+, QuickBasic, and now PowerBasic.

I agree, C isn't logical. Why this bizarre and ugly hack of a PDP-11
assembler got to be the programming standard is beyond me. We're
paying the price big time.

John

 

[Steve Evans]

On Wed, 13 Oct 2004 22:58:47 GMT, "Joe Rocci" <joe@roccis.com> wrote:

Thanks for the explanation, Joe, but no. I never said anythink about
multiplicaiton

Steve,
Can you send me a copy of the original post? When these things happen, I
like to see where my crazy notions came from.

Here it is in its entirety....

Hi everyone,

Below you will find my attempt to show in text-form, a circuit
fragment from a 145Mhz amplifier:


--------------capacitor-------------------------------transistor base
|
|
I
|
coil
|
|
|
|
------------------------------------------------------------GND

The cap's value is 1nF; the inductor's is 0.4uH.
The cap (I assume) is to couple one amplifier stage into the next
(50ohm source/load) with minimal attenuation of the desired VHF
signal. But like what's the purpose of this inductor to ground??
--

Fat, sugar, salt, beer: the four essentials for a healthy diet.

 

[Steve Evans]

On Tue, 12 Oct 2004 17:10:41 -0500, "Steve Nosko"
<suteuve.nosukowicuz@moutouroula.com> wrote:

This could be viewed as what we call a "clamper circuit" The AC voltage
AT THE BASE will have its positive peak "clamped" or moved to +0.7 volts and
the waveform will extend from there as negative as the waveform is tall.

IF we had 5 volts peak (10 volts peak-to-peak) the cap left side, the base
voltage will swing from +0.7 volts to -9.3 volts.

Okay, upon further thought about this there's still something amiss in
my understanding. I take what you say about the cap blocking out the
DC component of the waveform to leave the AC largely unaffected.
However, the term "clamping" AIUI means the diode lops off anything
over about 0.7 volts from the input waveform (ie, it conducts it away
to ground) so around half of it is lost (half wave rectification). Now
you state (and the spice progs agree) that what *actually* happens in
this case is that the whole AC waveform gets shifted south into
negative territory. It's still a full wave, but it's way down into
the negative and only the highest peaks just creep above zero volts.
Is this effect *solely* attributable to the steady build-up of
negative charge on the cap's RHS? I think what's really freaking me
out here is the fact that the signal source is grounded on the neg.
side and yet we have that same signal that after going through a cap
can end up going fully negative *below* ground. It just seems like any
such voltage beneath zero/ground potential is breaking the laws of
physics. Ground should be the 'absolute zero' of the potentials in any
circuit and here it is being violated. I need some help to get my
thick head around the concept! :-(
--

Fat, sugar, salt, beer: the four essentials for a healthy diet.

 

[colin]

"anonymous" <anonymous@catfarm.com> wrote in message
news:hkZ9d.212267$MQ5.19587@attbi_s52...

Im working on a power supply for some musical bits. Unfortunately its
producing a great deal of "hum" in the circuit. Is there any way to filter
out residual AC in the DC line?

What I have:

+18V (wall wart) ---->3500uF
(electrolytic) ---->.22uF--->7809--->.1uF--->out
|
| |
ground
ground ground

the ground is common between the wall wart and all components. There are 4
7809s in parallel at the output.

If youve got any humm in the dc output still then something is wrong as it
sugests the regulator is dropping out. ie the input voltage is diping too
loo for the regulator to compensate.

Whats also likely is that you have ground or signal loops that are picking
up mains humm, particularly if you have a few bits of equipment conected
together or long signal leads earthed at both ends etc ..

Colin =^.^=

 

[John]

On 13 Oct 2004 23:26:57 -0700, bokiteam@ms21.hinet.net (boki) wrote:

Dear All,
I want to implement a simple A/D conversion by PC sound card
input channel(Line in / MIC in), therefore I can employ it as a high
resolution A/D processor ?

What is the limit/problem in hardware?

Thank you very much for your comments.

Best regards,
Boki.

You will probably be better served by a device made for the purpose.

http://www.dataq.com/194.htm

This a 4 channel, 10 bits/channel D/A converter with software for
$25US

 

[anonymous]

"tempus fugit" <toccata@no.spam.ciaccess.com> wrote in message
news:fU%9d.336$57.170@fe51.usenetserver.com...

Is this to power guitar effects by any chance? If your components are
working properly, you might want to look into the possibility of a ground
loop somewhere. For instance, if you have your amp plugged in one outlet,
and your effects power supply in another one on the other side of the
room,
you're almost guaranteed to create a ground loop. Try plugging all the
gear
your plugging into into one outlet or power bar and see if the hum goes
away. Alternately, try unplugging (from the wall) each piece of equipment
one at a time to see if the hum goes away. If it does, you've found the
problem.

yes these are guitar effects. they are all plugged into the same power
strip. they work properly (normally).

 

[Joe Rocci]

Thanks for re-posting that Steve. I don't know where I got the crazy idea
that this was a multiplier stage....maybe I'm confusing this with a
different thread.

Thanks
Joe
W3JDR

Steve Evans <smevans@jif-lemon.co.mars> wrote in message
news:gastm0hvua613usng7ued0kl399s5a2j76@4ax.com...

On Wed, 13 Oct 2004 22:58:47 GMT, "Joe Rocci" <joe@roccis.com> wrote:

Thanks for the explanation, Joe, but no. I never said anythink about
multiplicaiton

Steve,
Can you send me a copy of the original post? When these things happen, I
like to see where my crazy notions came from.

Here it is in its entirety....

Hi everyone,

Below you will find my attempt to show in text-form, a circuit
fragment from a 145Mhz amplifier:


--------------capacitor-------------------------------transistor base
|
|
I
|
coil
|
|
|
|
------------------------------------------------------------GND

The cap's value is 1nF; the inductor's is 0.4uH.
The cap (I assume) is to couple one amplifier stage into the next
(50ohm source/load) with minimal attenuation of the desired VHF
signal. But like what's the purpose of this inductor to ground??
--

Fat, sugar, salt, beer: the four essentials for a healthy diet.

 

[jm]

No, I'd just make a standalone and glue it to the device. I've seen them
cheap on ebay, but thought I might take a whack at it.


"Mike" <no_spam@comcast.net> wrote in message
news:gqidnYlaqawsBPfcRVn-vg@comcast.com...

In terms of TV/VCR remotes and the like, they're not constantly
powered-on,
so there'd be no reply signal to a device you would make. I think the same
applies to cordless phones.

Mike

"jm" <john_20_28_2000@yahoo.com> wrote in message
news:c67e4bdd.0410101942.64820fb2@posting.google.com...
I am going to build a device like a remote control finder. I think I
could eventually figure out a circuit that makes a noise, but what
would I look at for the wireless part of it? Should I just take apart
my cordless phone and look!

Thanks, don't know what to look at.

---

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/2004

 

[Rodney Kelp]

If you are targeted what on earth have you done? or are planning to do?
On the other hand if you have nothing to hide why would they waste their
time and resources to watch you?

"Soundweapon" <soundweapon@cs.com> wrote in message
news:20041014194621.18589.00002580@mb-m29.news.cs.com...

Classified US Government Technology

The United States government now has surveillance technology than can
electronically see and hear through walls. Agents of the US government can
move
into a neighboring house and conduct complete surveillance of you in your
home
completely without your knowledge. The agents will never have to enter
your
home and place bugs because all surveillance is done electronically
through the
walls of your home. All your movements and conversations in your own home
can
be videotaped and analyzed without your knowledge. This technology in
effect
gives agents of the US government X-ray vision and they can use it to see
right
into your bedroom.

This US government has also incorporated this technology into targeting
scopes
that can identify and target a person through walls. This targeting scope
combined with a high powered rifle can assassinate a person through walls.

This technology was developed to protect the national security of the
United
States but has been illegally turned against US citizens by agents of the
US
government. Agents of the US government are covertly working with local
law
enforcement to conduct illegal surveillance of innocent US civilians.
Citizens
have no defense against this technology. You may never know you're under
surveillance and even if you were made aware, there is nothing you can do
about
it. No electronic detection equipment is available to detect the
surveillance
technology. If you're targeted, you're on your own because no one can help
you.
For more information, please visit the website listed below.

Website:
http://ourworld.cs.com/soundweapon/


Soundweapon@cs.com

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/2004

 

[Gill]

Thank you Tom for your help. My husband thought that a diode would need to
be used...he seemed to remember that bit of information from his highschool
days. Yes, we've been trying to do research...that's why it has been so
frustrating not to have made more progress to this point. It's great
getting different perspectives from others...we appreciate the feedback and
help.

Renee

"Tom MacIntyre" <tom__macintyre@hotmail.com> wrote in message
news:lerqm0pej7s77v94ctb6i5t35htpequshg@4ax.com...

On Wed, 13 Oct 2004 10:26:07 -0700, "Gill"
gkgill@adelphiaschmelphia.net> wrote:

Hi, I'm hoping someone out there can help me. I have a seventh grade son
who must do a Science Fair project. He has chosen to do a project based
on
"Alternative Energy". His goal is to power his GameBoy using some form
of
power other than batteries or electricity. Any and all alternative
energy
sources are being considered.

A Game Boy is likely to not like unregulated power, so you may want to
consider that. A diode bridge, a filter capacitor, a zener diode, and
the appropriate dropping resistor would possibly do the trick in the
right configuration. They may be internally regulated, though...maybe
someone here knows if that is the case.

I don't know what the voltage requirement is (6 VDC?). Perhaps some
kind of miniature windmill turning a generator, or motor connected in
reverse, driven by a variable fan? Hmmm...that may be out, as
something is needed to drive the fan...some kind of hand-cranked or
foot-cranked affair, maybe.

My son just informed me that a Game Boy is 2 cells/3 VDC...that's good
news, because it puts it closer to the range that the fruit and
vegetable battery can possibly provide, although I don't know if
you'll get enough power without a fairly substantial series/parallel
setup, and .

I'll try to check into this a bit more later; it looks like you've
done your share of research, so it isn't like you're asking for
someone to do the project for you (which would be frowned upon most
times at least).

Tom


The problem is that we have been unable to find any information that will
help us to achieve his goal. We have been to the library a number of
times;
we have checked the book store; stopped in at Radio Shack; and have
surfed
the Internet - all without luck. We are able to find books and websites
about Alternative Energy but they all just tell about what other energy
sources are out there (water, solar, static, etc.) but not information on
how to harness that energy and convert it to power for a particular
device.

I have read article refering to a man who converted his TV to be powered
by
in kids pedaling a bicycle but I can't find a "how to" for that either.
We've all seen the in Science books about powering a digital clock or
flashlight battery with a potato or lemon...could a series of potatoes
supply the 3 volts needed? We have tossed around a number of possible
approaches, including: potatoes; bicycle power; solar power; hand crank;
possible incorporation of a car alternator; and many more.

Any information on where to find instuctions for harnessing and
converting
alternative energy (or any other insight you might have) would be very
much
appreciated.

Thank you,

Renee

 

[Gill]

Well Rich...we like the VR suit idea...unfortunately if we haven't been able
to find the needed info for harnessing alternative energy, I guess I'm not
too hopeful for finding VR suit instructions...

Maybe we can save the VR idea for my son's highschool years.

Thanks

Renee

"Rich Grise" <rich@example.net> wrote in message
newsan.2004.10.14.02.05.22.66101@example.net...

On Wed, 13 Oct 2004 10:26:07 -0700, Gill wrote:

Hi, I'm hoping someone out there can help me. I have a seventh grade
son
who must do a Science Fair project. He has chosen to do a project based
on
"Alternative Energy". His goal is to power his GameBoy using some form
of
power other than batteries or electricity. Any and all alternative
energy
sources are being considered.

Design a VR suit that's coupled with cranks and levers and pushrods and
stuff to a generator, so the game is powered by the player's own
movements.

;-)

Good Luck!
Rich

 

[Kevin Aylward]

Wong wrote:

Hi,

Is it possible to saturate the NPN BJT transistor in this biasing ?
Vcc
___
|
|
|
_| C
B |
---- Resistor ----|
|
-
| E
|---------------- Output
|
Resistor
|
|
|
---
- Ground


Since the transistor is OFF when '0' to base and hence output is '0'.
Then when '1' to base I would like to have 4.5V at the output, is that
possible to bias the transistor in saturation region (since Vce no
more <0.2V)?

Yes, if you drive it with a voltage at least one diode drop above Vcc.
Otherwise, it wont saturate, only clip.

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.

 

[CFoley1064]

Subject: any replacement
From: nospam4ujack@yahoo.com (Jack)
Date: 10/15/2004 8:10 AM Central Daylight Time
Message-id: <e179813d.0410150510.1ac3ff52@posting.google.com

hi all

i need six, 2 input nand schmitt trigger gates in a single ic.

i just don't want to use 2, cd4093 ics. Is there any such ic which i can use?


thanks for reply

Hi, Jack. Sorry to say, I believe the part you're seeking doesn't exist.

If you want to use MML (Mickey Mouse Logic), you can kludge together a one-IC
solution with a 74C14 like this:

VCC
+
|
.-.
| |
| |
'-'
| |\
A o---|<--o--|H>O- o Q
| |/
|
B o---|<--o
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de


Q is low only when A AND B are high, and there is some hysteresis for the
second signal to change. It is slower than a standard gate, and there will be
more space and holes/pads than two ICs. I don't think this is better than two
ICs, but there it is.

Use two ICs.

Good luck
Chris

 

[Reg Edwards]

Sure did, Steve! I ran it through a spice program and you're right in
every detail.
=======================

What makes you think Spice is correct? Its only a buggy computer program.
Rubbish in - rubbish out!

 

[Rich Grise]

On Fri, 15 Oct 2004 11:42:40 -0700, D-Zyl wrote:

Hi,

I need to rotate a mass of 10kg around a vertical tube.
rotation will be of about 90 degrees.
the motor must be the smallest as possible.
how can I do to choose the right motor (power, technology, w/ or w/o gearbox...)
?
where can I find useful infos ???

You could use a pager motor, if you have a week to make the movement.

Good Luck!
Rich

 

[Rich Grise]

On Fri, 15 Oct 2004 02:12:31 -0700, Wong wrote:

Hi,

Is it possible to saturate the NPN BJT transistor in this biasing ?
Vcc
___
|
|
|
_| C
B |
---- Resistor ----|
|
-
| E
|---------------- Output
|
Resistor
|
|
|
---
- Ground


Since the transistor is OFF when '0' to base and hence output is '0'.
Then when '1' to base I would like to have 4.5V at the output, is that
possible to bias the transistor in saturation region (since Vce no
more <0.2V)?

Is "saturation" even meaningful in an emitter follower?

Thanks,
Rich