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The LED is not illuminated constantly. The duty cycle of a flashing LED is
about 10%,
er no !, the led needs to be really noticeable and a 10% duty cycle doesnt** Really - how ever did you get that ?
240 AC half wave = 170 volts rms.
With R =33 kohms ( = 10 mA peak) = 0.87 watts in the resistor.
The LED is not illuminated constantly. The duty cycle of a flashing LED
is about 10%, so divide your figure by 10, reaching a figure of less
than 100 milliwatts, as stated.
I need to acquire a couple of "bucket brigade" IC chips for my son's
Webelo troop. They are in an endeavor to attain some of their "activity
badges" and my son has chosen electronics (which he has shown a great
deal of talent in). He has done quite a few projects on his own but now
is taking a leadership role in helping his brother Webelos put together
an "Echo Chamber". If we can acquire these pieces he will be able to
complete the schematic he pulled off of the web. So if anyone can help
us (him) out it would be greatly appreciated. Also any messages with
the history of these chips, and other erata with regards to "Echo
Chambers" would be greatly appreciated. Thank you for your time and
consideration in this project.
Bill
** Cos he 'ad one of 'em.Why 10nF (0.01uF) capacitor and not 100nF (0.1uF)
and why 400V
And where do you get a 4W, 170 ohm resistor pray tell?
What type is the resistor, metal film/oxide, carbon film, wire-wound?
BTW are you in Australia where we use 240Vac, 50Hz?
http://www.smarthome.com.au/content/home/index.aspHi, I need some ideas about a home automation system! In two weeks time
in need to submit a project proposal. I need to know if it is possible
to develop a home automation system that is controlled directly from a
pc. I intend to control lights, get a live feed from a camera and also
if it is possible to control an air condition. Can someone please help
me with some ideas and suggestions?
Check out X10 - here's an Aussie link which may give some ideas:
That's why I said "dominant". (It is a fairly standard commercial practice.)Another poster mentioned using a capacitor to drop most of the voltage which
is a good idea as the power consumed by the device will be less than the
VA. It won't be a great power factor but this probably doesn't matter in
such a low powered device (I don't know the standards but at least in some
countries I think there is an exemption from the power factor requirements
for low powered devices.) Also since it will be capacitive, it will
probably improve the power factor of your house as a whole, by a miniscule
amount. I would not drop all of the voltage with a capacitor but I would
use a resistor to drop a few tens of volts in series with the capacitor. I
would do that because if there is a mains spike, the high dV/dt would cause
very high currents if there is no resistor in the circuit.
it would pay to consider the worst-case peak pulse power (and energy)On 13 Mar 2006 22:59:24 -0800, "Omid" <hojabri@gmail.com> wrote:
Thank you All!!!
My Circuit finally worked with your help.
I used X2 Class Cap(0.01u 400V) and R (4W - 170 Ohms)
and it works correctly!
Thanks again.
Why 10nF (0.01uF) capacitor and not 100nF (0.1uF) and why 400V (I
assume it was 400Vac)? Much bigger (physically) than needed.
And where do you get a 4W, 170 ohm resistor pray tell? Standard value
would be 180ohm.
What type is the resistor, metal film/oxide, carbon film, wire-wound?
You only need a 1W carbon film.
CheersBTW are you in Australia where we use 240Vac, 50Hz?
Is that $AUD or $USD?100 pcs PCB price:75$
Post Cost;50$
Total:125$
On 17 Mar 2006 11:17:42 -0800, "rowan194" <googlegroups@sensation.net.au
wrote:
Heywood Jablome wrote:
100 pcs PCB price:75$
Post Cost;50$
Total:125$
Is that $AUD or $USD?
It'll be USD for sure . That's the only international currency in Asian
manufacturing.
Yes, I knew what you were on about, but wanted to make sure that the reasonOn Tue, 14 Mar 2006 22:28:53 +0000, Chris Jones
lugnut808@nospam.yahoo.com> wrote:
Another poster mentioned using a capacitor to drop most of the voltage
which is a good idea as the power consumed by the device will be less than
the
VA. It won't be a great power factor but this probably doesn't matter in
such a low powered device (I don't know the standards but at least in some
countries I think there is an exemption from the power factor requirements
for low powered devices.) Also since it will be capacitive, it will
probably improve the power factor of your house as a whole, by a miniscule
amount. I would not drop all of the voltage with a capacitor but I would
use a resistor to drop a few tens of volts in series with the capacitor.
I would do that because if there is a mains spike, the high dV/dt would
cause very high currents if there is no resistor in the circuit.
That's why I said "dominant". (It is a fairly standard commercial
practice.)
most DVD players can display JPG images,Greetings group.
Someone wrote in to Silicon Chip mag. a while back with the idea of
burning tv test patterns onto a DVD for servicing tv's.
Does anyone have any files like this that they could email me.
I have done a search but cannot find anything useful.
Someone wrote in to Silicon Chip mag. a while back with the idea of
burning tv test patterns onto a DVD for servicing tv's.
Does anyone have any files like this that they could email me.
I have done a search but cannot find anything useful.
time I ordered something through them it took about 4 months with a"budgie" <me@privacy.net> wrote in message
news:bfqm12dbt3tto193clpou8apcd461fe8j8@4ax.com...
On 17 Mar 2006 11:17:42 -0800, "rowan194" <googlegroups@sensation.net.au
wrote:
Heywood Jablome wrote:
100 pcs PCB price:75$
Post Cost;50$
Total:125$
Is that $AUD or $USD?
It'll be USD for sure . That's the only international currency in Asian
manufacturing.
I guess no one has gone for it from this news group. I was hoping that
someone could confirm that this guy is legitimate. I think I will be a lab
rat and give it a go, as it doesn't look like a scam.
Will report back if I go for it. Currently I have 5 boards being made up by
Futurlec. I will need some more tho.
I hope futurlec have a faster turn around with PCB's than parts, last
HEY! I recognise that chair! I threw that one out on thehttp://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=4449792385
It's called bridging - there's probably heaps of info around on it. Somebruce varley <bxvarley@weqstnet.com.au> wrote in message news:...
Hi, This must be a common question, but I can't find anything relating to
it in back postings on my machine. What's the effect of parallelling two
stereo outputs to produce one mono one, without any interposing
resistance?
Can you actually break something by doing it with ordinary hifi-standard
gear? Is there any devastating effect on quality, I guess I'll hear it if
there is. TIA
Line level (Ca 100mV)
I think you've grabbed the ball and gone charging off for the wrong goalbruce varley wrote:
bruce varley <bxvarley@weqstnet.com.au> wrote in message news:...
Hi, This must be a common question, but I can't find anything
relating to it in back postings on my machine. What's the effect of
parallelling two stereo outputs to produce one mono one, without
any interposing resistance? Can you actually break something by
doing it with ordinary hifi-standard gear? Is there any
devastating effect on quality, I guess I'll hear it if there is.
TIA
Line level (Ca 100mV)
It's called bridging - there's probably heaps of info around on it.
Some dual channel sound-reinforcement (eg Rock PA) amps have it
built-in.