Chip with simple program for Toy

[Dominic-Luc Webb]

2. RB1 and RB2 have a 1K resistor, then what looks like two diodes. If
these are unused, are the diodes needed? If they're supposed to be LEDs,
1K seems high - I calculated my two sets of LEDs as needing 120Ohms
and 160Ohms?

Maybe you mean RB0 and RB1.... if the supply is 5 volts and these
are typical 5 mm 2.0 volt and 0.03 amp LEDs, then a typo would
make more sense. This would work out to exactly 100 Ohm, just
obeying Ohm's law.

I'll wait and see if anyone suggests an explanation for that
transistor. It would more more sense to me if the collector
and emitter were in reverse order. In that case, it would look
like the basic textbook example with 9 VDC to one speaker wire
and the other speaker wire going to collector and then the emitter
goes to ground, as usual.

Surely someone with more experience sees something I do not.

Dominic

 

[Danny T]

Andrew Holme wrote:

Well, I've answered your specific questions. I could go on, but this is a
MASSIVE subject. I recommend the book "The Art of Electronics" by Horowitz
and Hill if you fancy some good arm chair / bed time reading on the subject.
It's informal, readable and not at all stuffy or dry.

At Ł50, I think I'll see if the Library have it first ;-)

Ta!

--
Danny

 

[Dominic-Luc Webb]

The base, collector and emitter (B, C, E) are the three terminals of a
bipolar transistor. The base and collector are positive with respect to the
emitter of an NPN transistor. The reverse is true of a PNP transistor.

The emitter of an NPN transistor is not always connected to ground.

Is the emitter ever connected and actually running at a voltage that is
higher than the collector? Is this described in the Horowitz book?

Dominic

 

[Danny T]

Robert Monsen wrote:

At Ł50, I think I'll see if the Library have it first ;-)

Try bookpool. They had it for $50 US. Who knows now, though, with the
dollar having 'issues'?

$53... with $25 shipping to the UK... Even with the exchange rate in my
favour, that's gotta be over Ł40!

--
Danny

 

[Ricky Romaya]

NoSpam@daqarta.com (Bob Masta) wrote in
news:41d80947.1263957@news.itd.umich.edu:

On 01 Jan 2005 17:04:46 GMT, Ricky Romaya <something@somewhere.com
wrote:

Power amp gains are typically set so a "line level" of about 1 VRMS
will drive them to their maximum output, which depends mostly upon
the power supply rails... you size your devices to handle the rails.

Care to elaborate on this? I've noticed that the power amp op-amps have

their gain preset. Do you mean that to drive them to max output, you need
1 VRMS input? Take TBA820M for example, it's gain is preset to 20 (if not
mistaken), then a 1 VRMS input will give 20 VRMS output, and the power on
the 8 ohm speaker is then (20^2)/8 = 50W? But it says that TBA820M is a
2W power amp (on 8 ohm load and 12V rails).

TIA

 

[Andy]

Jim Douglas wrote:

BB909A/BB909B varicap diode. I bought a little FM transmitter to play with
and ended up breaking this diode. I can't seem to find one anywhere? Is
there an equivalent?

Thanks,

Jim Douglas

If you're ready to order from Europe, you might try

http://www.xs4all.nl/~barendh/Indexeng.htm

They have a minimum order of 15 Euro and delivery cost 7.50 worldwide.

I have not yet ordered from them.

 

[Bob Myers]

"George Dewar" <dewarg**NOSPAM**@nbnet.nb.ca> wrote in message
news:zM_Cd.204764$Np3.8607734@ursa-nb00s0.nbnet.nb.ca...

I would like to have somebody knowledgeable in electronics construct a
device
that would turn on at dusk and flash until dawn. I want to power it with
AA
batteries so I assume the best type of light would be a red LED.

What's the application? How far away (and in what direction, or
rather in how many directions) does it need to be visible? How long
do you need it to run unattended (i.e., before you could change the
batteries)? What environment? Is there no possibility of AC power
at all?

Bob M.

 

[John Popelish]

"M.Daughtry" wrote:

You need to catch the re-run of Myth Busters where they tested this very
thing. IIRC (because I really wasn't paying a whole lot of attention) their
conclusion was that it was plausible but not very likely (someone chime in
if I'm wrong).

I didn't see the show, but the antenna efficiency for this sort of
thing is extremely low. You would have to sit beside the transmitting
antenna to have a chance of it happening.

--
John Popelish

 

It's still speculated... see:

http://www.snopes.com/radiotv/tv/fillings.htm

I don't have any idea how it'd work, much less how the signal would be
demodulated...
However, I'd like to play devil's advocate and point out a few
things... first is that tissue does not make a good faraday cage. You
are a better conductor than rubber, but MUCH worse than copper. UHF
and VHF passes through you relatively easily.

Secondly, do you want to assume that, if this legend is true, the
filling induces sound in the mouth? Electrical impulses transmitted
around your auditory nerve definately seem like sound to the beholder.
Maybe that's the mechanism...?

Lastly, who's to say the filling acts as an antenna, a diode, or a
battery? A filling in a saline solution, surrounded by nerves, bone,
and other tissue might act completely differently than it would
stand-alone.

I dunno if it's true or not... it'd be interesting to get concrete
proof.

Dave

 

[Andrew Holme]

John Popelish wrote:

"M.Daughtry" wrote:

You need to catch the re-run of Myth Busters where they tested this
very thing. IIRC (because I really wasn't paying a whole lot of
attention) their conclusion was that it was plausible but not very
likely (someone chime in if I'm wrong).

I didn't see the show, but the antenna efficiency for this sort of
thing is extremely low. You would have to sit beside the transmitting
antenna to have a chance of it happening.

Sit beside the transmitter, chewing on a mouth full of OA91 germanium
diodes.

 

[Joe McElvenney]

Hi,

Then there's getting speech or music out of the gas stove.
That is a little more plausible as I seem to recall that a flame
can be used as an RF detector.

I once got a stream of water out of my electric wall socket
but that was just the folks upstairs leaving a water tap on and
then going on holiday.


Cheers - Joe

 

[Stranger in the dark]

"Joe McElvenney" <ximac@btinternet.com> wrote in message
news:VA.00000081.000f2457@btinternet.com...

Hi,

Then there's getting speech or music out of the gas stove.
That is a little more plausible as I seem to recall that a flame
can be used as an RF detector.

I once got a stream of water out of my electric wall socket
but that was just the folks upstairs leaving a water tap on and
then going on holiday.


Cheers - Joe

Ok, here's one for ya....

I was about 12 at the time. We had gone away for a couple hours - my mother,
younger brother and myself. We merely went to the store to pick up a couple
things, a total of 10 miles round trip. My Dad and I believe one other
person was at home. There was a hail storm came through that day and lasted
about 15 minutes. The house had a basement, 1st floor and 2nd floor. The
first floor in the kitchen - the dome which hung from the kitchen ceiling
lamp had hail and water in it. There was NO leaks in the roof, no leaks
evident in the bedroom above the kitchen. No way we could think of, for the
water/hail to have gotten in that dome. While I'm sure there must be some
reasonable explanation for it, it sure defied one and still does - at least
to the writing of this. That was the first and last we noticed that sort of
thing - in our time there.

 

[Don A. Gilmore]

"Stranger in the dark" <Onlytheshadowknows@darksecrets.com> wrote in message
news:VhgDd.34689$NC6.23940@newsread1.mlpsca01.us.to.verio.net...

Ok, here's one for ya....

I was about 12 at the time. We had gone away for a couple hours - my
mother,
younger brother and myself. We merely went to the store to pick up a
couple
things, a total of 10 miles round trip. My Dad and I believe one other
person was at home. There was a hail storm came through that day and
lasted
about 15 minutes. The house had a basement, 1st floor and 2nd floor. The
first floor in the kitchen - the dome which hung from the kitchen ceiling
lamp had hail and water in it. There was NO leaks in the roof, no leaks
evident in the bedroom above the kitchen. No way we could think of, for
the
water/hail to have gotten in that dome. While I'm sure there must be some
reasonable explanation for it, it sure defied one and still does - at
least
to the writing of this. That was the first and last we noticed that sort
of
thing - in our time there.

Maybe Jesus put it there...or your little brother.

 

[Stranger in the dark]

"Don A. Gilmore" <eromlignodNOSPM@kc.rr.com> wrote in message
news:345k7mF48bpmiU1@individual.net...

"Stranger in the dark" <Onlytheshadowknows@darksecrets.com> wrote in
message
news:MEgDd.34691$NC6.4362@newsread1.mlpsca01.us.to.verio.net...

"Don A. Gilmore" <eromlignodNOSPM@kc.rr.com> wrote in message
news:345i45F46iguqU1@individual.net...
"Stranger in the dark" <Onlytheshadowknows@darksecrets.com> wrote in
message
news:VhgDd.34689$NC6.23940@newsread1.mlpsca01.us.to.verio.net...
Ok, here's one for ya....

I was about 12 at the time. We had gone away for a couple hours - my
mother,
younger brother and myself. We merely went to the store to pick up a
couple
things, a total of 10 miles round trip. My Dad and I believe one other
person was at home. There was a hail storm came through that day and
lasted
about 15 minutes. The house had a basement, 1st floor and 2nd floor.
The
first floor in the kitchen - the dome which hung from the kitchen
ceiling
lamp had hail and water in it. There was NO leaks in the roof, no
leaks
evident in the bedroom above the kitchen. No way we could think of,
for
the
water/hail to have gotten in that dome. While I'm sure there must be
some
reasonable explanation for it, it sure defied one and still does - at
least
to the writing of this. That was the first and last we noticed that
sort
of
thing - in our time there.


Maybe Jesus put it there...or your little brother.




Nah, don't think so...... Little brother couldn't reach it and beside, he
was with us! Jesus - well, to each his own - but I don't think such a
person/entity would waste their time doing stupid tricks like that. Try
again.


Batman?

Hmmmmm. Yeah, maybe.

 

[Don A. Gilmore]

"Stranger in the dark" <Onlytheshadowknows@darksecrets.com> wrote in message
news:MEgDd.34691$NC6.4362@newsread1.mlpsca01.us.to.verio.net...

"Don A. Gilmore" <eromlignodNOSPM@kc.rr.com> wrote in message
news:345i45F46iguqU1@individual.net...
"Stranger in the dark" <Onlytheshadowknows@darksecrets.com> wrote in
message
news:VhgDd.34689$NC6.23940@newsread1.mlpsca01.us.to.verio.net...
Ok, here's one for ya....

I was about 12 at the time. We had gone away for a couple hours - my
mother,
younger brother and myself. We merely went to the store to pick up a
couple
things, a total of 10 miles round trip. My Dad and I believe one other
person was at home. There was a hail storm came through that day and
lasted
about 15 minutes. The house had a basement, 1st floor and 2nd floor.
The
first floor in the kitchen - the dome which hung from the kitchen
ceiling
lamp had hail and water in it. There was NO leaks in the roof, no leaks
evident in the bedroom above the kitchen. No way we could think of, for
the
water/hail to have gotten in that dome. While I'm sure there must be
some
reasonable explanation for it, it sure defied one and still does - at
least
to the writing of this. That was the first and last we noticed that
sort
of
thing - in our time there.


Maybe Jesus put it there...or your little brother.




Nah, don't think so...... Little brother couldn't reach it and beside, he
was with us! Jesus - well, to each his own - but I don't think such a
person/entity would waste their time doing stupid tricks like that. Try
again.

Batman?

 

[Andrew Holme]

Danny T wrote:

Robert Monsen wrote:
I'm currently using 16F627 and 12F629. What section of the datasheet
was it under, so I can check what these say?

It's under 'special features of the CPU', where it talks about MCLR

For the PIC16F627, it reads

The on-chip POR circuit holds the chip in reset until
VDD has reached a high enough level for proper operation.
To take advantage of the POR, just tie the MCLR
pin through a resistor to VDD. This will eliminate external
RC components usually needed to create Power-on
Reset. A maximum rise time for VDD is required. See
Electrical Specifications for details.

The only references in electrical specs I can see are:

Voltage on MCLR and RA4 with respect to VSS -0.3 to +14V

and

Voltage spikes below VSS at the MCLR pin, inducing currents greater
than 80 mA, may cause latch-up. Thus, a series resistor of 50-100W
should be used when applying a "low" level to the MCLR pin rather
than pulling this pin directly to VSS.

But I'm pulling MCLR *up*, to stop it resetting, aren't I?! :-\


As far as your circuit goes, if you use these pullups, you don't
have to
connect the port to anything, it will automatically read as high when
you look at it, and won't consume inordinate amounts of power.

You can also use this to your advantage with pushbuttons, for
example.
Use a normally open pushbutton, set the port to use the internal weak
pullups, and connect the other side to ground. Then, if you push the
button, the port will read 0, otherwise, it'll read high.

If you aren't using the port, however, you can just set it to be an
output using the TRIS register, and then safely leave it unconnected.

Cool, that'll save me a few components then!
So if it's configured as an input, and pull-ups are enabled, I don't
need any resistors, but just leave it unconnected, or connected
directly to ground for a high/low respectively?

Correct. You don't need external pull-up resistors on your inputs if you
enable the internal pull-up facility.

 

[JeffM]

a device that would turn on at dusk and flash until dawn.
I want to power it with AA batteries...red LED
George Dewar

Another weenie with a half-formed idea.

|How far away (and in what direction, or rather in how many directions)
|does it need to be visible?
|How long do you need it to run...before you...change the batteries ?
|What's the application?
| Bob Myers
|
....and what is the duration of the "flash"? How often will it flash?
Duty cycle will be important for battery life.

 

[Robert Monsen]

George Dewar wrote:

I would like to have somebody knowledgeable in electronics construct a device
that would turn on at dusk and flash until dawn. I want to power it with AA
batteries so I assume the best type of light would be a red LED.

Possibly such a device might be commercially available.

4.5V (3x AA battery)
---------o----o----------o-------------------o--------.
| | | | |
| | | .-. V 1N4148
| | | 470k | | -
.-. | | | | |
220k | |<--' | '-' |
pot | | | | V 1N4148
'-' | | -
| | >| |
| | 2N3906 |------o
| CMOS | /| |
| 555 | | |
| __ | | |
.------|--------1| |o-' RED LED | |
| | .----o| |o-------------|<------o |
| | | -o| |o---------------------o |
| o--------o|__|o------. | |
| | | | | |
| | | | | |
| | '----------------|--------------o |
| | | | |
| .-----. | | |
| | LDR | | | .-.
| | | --- 1uF --- 1uF | | 100k
| '-----' --- --- | |
| | | | '-'
| | | | |
-----o------o--------------------o--------------o--------'
Ground

(created by AACircuit v1.28 beta 10/06/04 www.tech-chat.de)

Buy an LDR (a light sensitive resistor) from radio shack or wherever,
and measure it at the darkness you want the thing to turn on at. Then,
buy a pot that is about twice that value of resistance. Build the
circuit, and adjust the pot so the 555 turns on when it gets dark.

The larger the resistance of the LDR, the better, from a battery
perspective. You can also use a 9V battery for this circuit, which might
be more convienient, but won't last as long.

It will flash every second or so. You can adjust the flash rate by
changing the 470k resistor. Using a 9V battery may increase the time
between flashes.

YMMV. I haven't constructed it.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

 

[Robert Monsen]

AcCeSsDeNiEd wrote:

Hi guys. I have a LCD monitor. I lost the power adaptor for it.
I bought a replacement.

My LCD monitor power requirements are: 24V DC, 2.4A

My power adaptor is: 24V DC, 5A Max.

Question is, if the adaptor is 5A max, will it blow my LCD monitor?

Thanks

To e-mail, remove the obvious

No, it's fine. Your monitor draws only what it needs, which is less than
2.4A.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

 

[YD]

On Thu, 06 Jan 2005 12:53:50 -0500, John Popelish <jpopelish@rica.net>
wrote:

Andrew Holme wrote:

John Popelish wrote:
"M.Daughtry" wrote:

You need to catch the re-run of Myth Busters where they tested this
very thing. IIRC (because I really wasn't paying a whole lot of
attention) their conclusion was that it was plausible but not very
likely (someone chime in if I'm wrong).

I didn't see the show, but the antenna efficiency for this sort of
thing is extremely low. You would have to sit beside the transmitting
antenna to have a chance of it happening.

Sit beside the transmitter, chewing on a mouth full of OA91 germanium
diodes.

Aluminum foil gum wrappers against amalgam filling might also rectify
a bit.

BTDT. The galvanic current going through the root keeps you way too
busy getting rid of it to bother listening for radio emissions.

- YD.

--
Remove HAT if replying by mail.