Chip with simple program for Toy

"ted" <strnbrg59@gmail.com> wrote in message
news:2e36ce49-023b-40e8-ab2d-87867024c4c6@q24g2000prf.googlegroups.com...
I have a microcontroller and some other devices on a circuit powered
by a 5V power supply. The "other devices" consume a lot of current so
I'd like the microcontroller to turn them on only when they're
needed. I know how to do that with a transistor with its base
connected to the microcontroller. The trouble is that this would
supply the other devices with about 4.38V at most, and they really
need 5V (or very close to it). Is there any way to switch on the full
5V to those other devices on my circuit?
Click to expand...
You don't say what current you need.
Here is one device that will do that if 140mohms doesn't give you too much
drop:
http://www.linear.com/pc/productDetail.jsp?navId=LTC4411
They can be parralled if needed, but in that case you are probably better
off finding a higher current device.

Dave.
 
"Amit" <amit.kohan@gmail.com> wrote in message
news:9cbf4aa7-fbf9-4e03-9e2f-aeb1a2e98a7c@m73g2000hsh.googlegroups.com...
hello,

i'm a programmer who currently have started learning microcontroller
programming (arm) using c. one thing that i'm worry about is that i am
not expert in analog or electronic. what should i know or learn about
electonic in order to get a career in this field?

in past, i used logic analyzer and oscilloscope back in school but
haven't used them for a long time.

please let me know what topic in electronic I need to learn for this
important?
Click to expand...
You don't necessarily need electronics skills to be a good and useful
embedded programmer, as long as there is a good EE guy in the team. It's
usually the smaller companies with smaller R&D teams that require you to be
more of a "jack of all trades".

But it helps of you can drive a digital storage oscilloscope and logic
analyser. You'll also need to know about I2C, JTAG, SPI, RS232, RS485, USB
and other interfaces and how to debug them.

You might need some FPGA/VHDL knowledge if you are working on enbedded soft
core processors.

Dave.
 
"Amit" <amit.kohan@gmail.com> wrote in message
news:9cbf4aa7-fbf9-4e03-9e2f-aeb1a2e98a7c@m73g2000hsh.googlegroups.com...
hello,

i'm a programmer who currently have started learning microcontroller
programming (arm) using c. one thing that i'm worry about is that i am
not expert in analog or electronic. what should i know or learn about
electonic in order to get a career in this field?

in past, i used logic analyzer and oscilloscope back in school but
haven't used them for a long time.

please let me know what topic in electronic I need to learn for this
important?
Click to expand...
You don't necessarily need electronics skills to be a good and useful
embedded programmer, as long as there is a good EE guy in the team. It's
usually the smaller companies with smaller R&D teams that require you to be
more of a "jack of all trades".

But it helps of you can drive a digital storage oscilloscope and logic
analyser. You'll also need to know about I2C, JTAG, SPI, RS232, RS485, USB
and other interfaces and how to debug them.

You might need some FPGA/VHDL knowledge if you are working on enbedded soft
core processors.

Dave.
 
"C. Nick Kruzer" <insula@webtv.net> schreef in bericht
news:21601-4848AB73-1020@storefull-3256.bay.webtv.net...
I have two identical electronic ballasts that will each power a 20 Watt
tubular fluorescent light bulb.

Will the two 20W ballasts drive a single 40W tubular fluorescent light
bulb if the two ballasts are connected (parallel) to the 40 Watt
fluorescent bulb?

insula

(The 20W bulbs are removed from the two circuits before connecting the
ballast circuits to the 40W bulb.)
Click to expand...
No. These ballasts produce a (relative) high frequency AC voltage. As they
are not synchronized, they will blow each other.

petrus bitbyter
 
"C. Nick Kruzer" <insula@webtv.net> schreef in bericht
news:21601-4848AB73-1020@storefull-3256.bay.webtv.net...
I have two identical electronic ballasts that will each power a 20 Watt
tubular fluorescent light bulb.

Will the two 20W ballasts drive a single 40W tubular fluorescent light
bulb if the two ballasts are connected (parallel) to the 40 Watt
fluorescent bulb?

insula

(The 20W bulbs are removed from the two circuits before connecting the
ballast circuits to the 40W bulb.)
Click to expand...
No. These ballasts produce a (relative) high frequency AC voltage. As they
are not synchronized, they will blow each other.

petrus bitbyter
 
"C. Nick Kruzer" <insula@webtv.net> wrote in message
news:21601-4848AB73-1020@storefull-3256.bay.webtv.net...
I have two identical electronic ballasts that will each power a 20 Watt
tubular fluorescent light bulb.

Will the two 20W ballasts drive a single 40W tubular fluorescent light
bulb if the two ballasts are connected (parallel) to the 40 Watt
fluorescent bulb?

insula

(The 20W bulbs are removed from the two circuits before connecting the
ballast circuits to the 40W bulb.)

I wouldn't do that.
Click to expand...
The THD ( total harmonic distortion) would increase and could present a
dangerous situation.
Without knowing the specs on your device I could only guess this.
The unit may even power the 40 Watt lamp alone.
I just wouldn't do it considering the cost of the proper unit.

Tom
 
"C. Nick Kruzer" <insula@webtv.net> wrote in message
news:21601-4848AB73-1020@storefull-3256.bay.webtv.net...
I have two identical electronic ballasts that will each power a 20 Watt
tubular fluorescent light bulb.

Will the two 20W ballasts drive a single 40W tubular fluorescent light
bulb if the two ballasts are connected (parallel) to the 40 Watt
fluorescent bulb?

insula

(The 20W bulbs are removed from the two circuits before connecting the
ballast circuits to the 40W bulb.)

I wouldn't do that.
Click to expand...
The THD ( total harmonic distortion) would increase and could present a
dangerous situation.
Without knowing the specs on your device I could only guess this.
The unit may even power the 40 Watt lamp alone.
I just wouldn't do it considering the cost of the proper unit.

Tom
 
"ted" <strnbrg59@gmail.com> wrote in message
news:2e36ce49-023b-40e8-ab2d-87867024c4c6@q24g2000prf.googlegroups.com...
I have a microcontroller and some other devices on a circuit powered
by a 5V power supply. The "other devices" consume a lot of current so
I'd like the microcontroller to turn them on only when they're
needed. I know how to do that with a transistor with its base
connected to the microcontroller. The trouble is that this would
supply the other devices with about 4.38V at most, and they really
need 5V (or very close to it). Is there any way to switch on the full
5V to those other devices on my circuit?
Click to expand...
Using a FET or a relay has already been mentioned. However, a saturated
transistor will have an on voltage, collector to emitter, far lower than
0.62 Volts. In most transistors it will be around 0.2 to 0.3 Volts.

One of the definitions of saturation is where the collector voltage falls
below the base voltage.

If it is really critical, you need to boost the regulator output a
corresponding amount to insure an exact voltage on the devices or locally
regulate it from a higher voltage. Unless this voltage is a DAC/ADC
reference or some such thing why is to so critical?
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:d43j441p3utgmsdt1qbbjmeh9u3fe6n5is@4ax.com...
On Fri, 6 Jun 2008 08:17:42 -0700, "Bob Eld" <nsmontassoc@yahoo.com
wrote:


"ted" <strnbrg59@gmail.com> wrote in message
news:2e36ce49-023b-40e8-ab2d-87867024c4c6@q24g2000prf.googlegroups.com...
I have a microcontroller and some other devices on a circuit powered
by a 5V power supply. The "other devices" consume a lot of current so
I'd like the microcontroller to turn them on only when they're
needed. I know how to do that with a transistor with its base
connected to the microcontroller. The trouble is that this would
supply the other devices with about 4.38V at most, and they really
need 5V (or very close to it). Is there any way to switch on the full
5V to those other devices on my circuit?

Using a FET or a relay has already been mentioned. However, a saturated
transistor will have an on voltage, collector to emitter, far lower than
0.62 Volts. In most transistors it will be around 0.2 to 0.3 Volts.

---
That's if it's an NPN and he's using it as a low side driver or if
it's a PNP and he's using it as a high side driver.

From his description I'd guess that he's using an NPN as an emitter
follower and it'll _never_ go into saturation.

JF
Click to expand...
Yeah, clearly an emitter follower would not be applicable. I didn't even
consider that the OP would try to go down that road.
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:d43j441p3utgmsdt1qbbjmeh9u3fe6n5is@4ax.com...
On Fri, 6 Jun 2008 08:17:42 -0700, "Bob Eld" <nsmontassoc@yahoo.com
wrote:


"ted" <strnbrg59@gmail.com> wrote in message
news:2e36ce49-023b-40e8-ab2d-87867024c4c6@q24g2000prf.googlegroups.com...
I have a microcontroller and some other devices on a circuit powered
by a 5V power supply. The "other devices" consume a lot of current so
I'd like the microcontroller to turn them on only when they're
needed. I know how to do that with a transistor with its base
connected to the microcontroller. The trouble is that this would
supply the other devices with about 4.38V at most, and they really
need 5V (or very close to it). Is there any way to switch on the full
5V to those other devices on my circuit?

Using a FET or a relay has already been mentioned. However, a saturated
transistor will have an on voltage, collector to emitter, far lower than
0.62 Volts. In most transistors it will be around 0.2 to 0.3 Volts.

---
That's if it's an NPN and he's using it as a low side driver or if
it's a PNP and he's using it as a high side driver.

From his description I'd guess that he's using an NPN as an emitter
follower and it'll _never_ go into saturation.

JF
Click to expand...
Yeah, clearly an emitter follower would not be applicable. I didn't even
consider that the OP would try to go down that road.
 
In <14555-484A03EA-1129@storefull-3253.bay.webtv.net>, C. Nick Kruzer wrote
in part:

TWO 20W ballasts in parallel WILL shorten the
life of the tube electrodes by applying too much
heating current, hence releasing mercury inside
the tube from the electrodes.

Mercury!!...I don't want to become the "Mad Hatter"! :)
Click to expand...
That was talking about evaporating mercury from the electrodes to the
inside of the tubing.

This is somewhat incorrect - in normal operation, the electrodes
are too hot to have any mercury at all on them.

Overheating the electrodes will merely shorten their life by
accelerating evaporation of the thermionically emissive material that
the electrodes are coated with.

In any case, the mercury stays inside the tube.

Combining ballasts is merely a *Big Bad Idea* for the other reasons
(edited out for space). You are unlikely to match the proper wattage and,
voltage, the electrodes have a fair chance of shortened life, and the
ballasts are independent high frequency AC generators that are unlikely to
synchronize with each other.

One more good reason - UL listing of electrical equipment (including
fluorescent lamp ballasts) is invalid when they are used other than as
directed. Your fire insurance company and your landlord may cause you
major grief if you burn up your apartment (and any other apartments) from
abused ballasts going KABLOOEY, as opposed to having a fire starting from
them despite using them as directed (which is presumably much more
unlikely).

- Don Klipstein (don@misty.com)
 
In <14555-484A03EA-1129@storefull-3253.bay.webtv.net>, C. Nick Kruzer wrote
in part:

TWO 20W ballasts in parallel WILL shorten the
life of the tube electrodes by applying too much
heating current, hence releasing mercury inside
the tube from the electrodes.

Mercury!!...I don't want to become the "Mad Hatter"! :)
Click to expand...
That was talking about evaporating mercury from the electrodes to the
inside of the tubing.

This is somewhat incorrect - in normal operation, the electrodes
are too hot to have any mercury at all on them.

Overheating the electrodes will merely shorten their life by
accelerating evaporation of the thermionically emissive material that
the electrodes are coated with.

In any case, the mercury stays inside the tube.

Combining ballasts is merely a *Big Bad Idea* for the other reasons
(edited out for space). You are unlikely to match the proper wattage and,
voltage, the electrodes have a fair chance of shortened life, and the
ballasts are independent high frequency AC generators that are unlikely to
synchronize with each other.

One more good reason - UL listing of electrical equipment (including
fluorescent lamp ballasts) is invalid when they are used other than as
directed. Your fire insurance company and your landlord may cause you
major grief if you burn up your apartment (and any other apartments) from
abused ballasts going KABLOOEY, as opposed to having a fire starting from
them despite using them as directed (which is presumably much more
unlikely).

- Don Klipstein (don@misty.com)
 
"Dave.H" <the1930s@googlemail.com> wrote in message
news:d09de802-06f9-4eda-95e9-2da9a7535969@z24g2000prf.googlegroups.com...
I've been looking for a simple (preferably 1 or 2 transistors or IC
based) preamp to go between the LM380 amp I mentioned in an earlier
post, and a regen radio. I've searched Google and only came up with
circuits that are too complicated for me (only have basic electronic
skills). I found one at Jaycar electronics, but would prefer to roll
my own. Any help on this is appreciated.

Thanks
Dave
Australia
Click to expand...
First hit on google search for transistor preamp. Appears to be pretty basic
and would likely rank as beginner material.
http://www.uoguelph.ca/~antoon/circ/amp1.htm

One that explains the design of another one (I haven't read this, so I can't
vouch for accuracy):
http://www.rason.org/Projects/bipolamp/bipolamp.htm

Many, many, many more.

Good luck,
Richard
 
"Dave.H" <the1930s@googlemail.com> wrote in message
news:d09de802-06f9-4eda-95e9-2da9a7535969@z24g2000prf.googlegroups.com...
I've been looking for a simple (preferably 1 or 2 transistors or IC
based) preamp to go between the LM380 amp I mentioned in an earlier
post, and a regen radio. I've searched Google and only came up with
circuits that are too complicated for me (only have basic electronic
skills). I found one at Jaycar electronics, but would prefer to roll
my own. Any help on this is appreciated.

Thanks
Dave
Australia
Click to expand...
First hit on google search for transistor preamp. Appears to be pretty basic
and would likely rank as beginner material.
http://www.uoguelph.ca/~antoon/circ/amp1.htm

One that explains the design of another one (I haven't read this, so I can't
vouch for accuracy):
http://www.rason.org/Projects/bipolamp/bipolamp.htm

Many, many, many more.

Good luck,
Richard
 
JANDRMUSICWORLDSUXMOOSEWANG <jandrmusic.worldsux@gmail.com> wrote in
news:04e61162-53d7-49e9-8ca0-db0d22a04106@2g2000hsn.googlegroups.com:

They sell crap and they steal from their customers
Click to expand...
It'd be more useful if you at least described the nature of your complaint
- without any description, you comment doesn't mean much.

I get stuff from them via Amazon.com soemwhat frequently and have had no
problems.
 
JANDRMUSICWORLDSUXMOOSEWANG <jandrmusic.worldsux@gmail.com> wrote in
news:04e61162-53d7-49e9-8ca0-db0d22a04106@2g2000hsn.googlegroups.com:

They sell crap and they steal from their customers
Click to expand...
It'd be more useful if you at least described the nature of your complaint
- without any description, you comment doesn't mean much.

I get stuff from them via Amazon.com soemwhat frequently and have had no
problems.
 
"Bob Monsen" <rcmonsen@gmail.com> wrote in message
news:vvK2k.210$cW3.167@nlpi064.nbdc.sbc.com...
"Bill Bowden" <wrongaddress@att.net> wrote in message
news:36e15247-37e5-46be-97cc-312cdd5ebfcc@26g2000hsk.googlegroups.com...
Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

Thanks,

-Bill


http://www.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf
Click to expand...
This guy Al Kaline was not only a fabulous baseball player (over 3000 career
hits), but he apparently makes a hell of a battery, too!

Bob
--
== NOTE: I automatically delete all Google Group posts due to uncontrolled
SPAM ==
 
"Tim Wescott" <tim@seemywebsite.com> wrote in message
news:sMOdnddNudorltHVnZ2dnUVZ_tfinZ2d@web-ster.com...
On Sat, 07 Jun 2008 22:31:26 -0700, Bill Bowden wrote:

Can't seem to locate any battery specs for Alkaline "D" cells. Tried the
Duracell and Raovac sites, but couldn't find much data for standard
cells. Read a few notes indicating the capacity of a standard "D cell"
is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

Thanks,

-Bill

If you design things to work all the way down to 0.9V/cell then it'll be
a better fit for NiMHs, and you'll wring a tad more running time out of
your battery.

You may find that at such a low current you're limited by the shelf life
of the battery (you certainly will be for NiMHs!). Unfortunately that
particular data sheet doesn't give it, but alkaline cells seem to last
for years on the shelf, so it may not be that much of a consideration.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com
Click to expand...
Take a look at the so-called "hybrid" NiMH batteries. They claim MUCH longer
shelf life, and as a side benefit of this, they come pre-charged.

There are a few manufacturers of this new technology. Sanyo (Eneloop brand)
is one of them:

http://www.eneloopusa.com/eneloop.html

http://www.eneloop.info/fileadmin/redakteur/Articles/Teraoka_Article_EN.pdf

Bob
--
== NOTE: I automatically delete all Google Group posts due to uncontrolled
SPAM ==
 
"Bill Bowden" <wrongaddress@att.net> wrote in message
news:36e15247-37e5-46be-97cc-312cdd5ebfcc@26g2000hsk.googlegroups.com...
Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?
Click to expand...

AAA = 1 AH
AA = 2
C = 5
D = 10

Note that each capacity is max. Max capacity for each size occurs at a
different current.
Your application may be limited by operating temperature and shelf life.
 
"Bill Bowden" <wrongaddress@att.net> wrote in message
news:36e15247-37e5-46be-97cc-312cdd5ebfcc@26g2000hsk.googlegroups.com...
Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?
Click to expand...
http://data.energizer.com/PDFs/E95.pdf

Note that the capacity vs discharge curves don't go down that low for D
cells. You could try and extrapolate the curves, but that's only guessing.
When you get to figures this low you are talking 40000 hours+, the shelf
life of the battery.

If you want to use the full capacity of the battery then you need to have a
0.9V cutoff or slightly lower. 1.1V will be wasting a fair bit of the
capacity.

What is your application?

Dave.
 
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