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Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
If the currents were not identical where the difference current go?
I'm not sure we have evidence yet that Mr. Soap knows what he wasIn article <Xns9656B81A0AFDE831041831041@130.133.1.4>,
Joe Soap <me@privacy.net> wrote:
|
| So try feeding a lamp via a diode, and report back on the flicker.
snip a bunch of correct stuff
I'm not sure if that's what you were getting at, Mr Soap, or not.
A diode in the feed is the easiest way of getting 50Hz flicker; full waveI'm not sure if that's what you were getting at, Mr Soap, or not.
Reason for the flicker at 50Hz with a diode is more a function of theA diode in the feed is the easiest way of getting 50Hz flicker; full wave
rectification is irrelevant to the discussion. If you feed a sine wave
oscillator at 50Hz to a power amplifier driving a bulb, you will also get
noticeable flicker. The flicker effect will vanish at about 70Hz.
Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
I do not wish to sound terse but when you get through that book at theBoris Mohar wrote:
On 14 May 2005 13:45:20 -0700, "Dave" <davidqanta@yahoo.com> wrote:
Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
Current in is same as current out. That is the LAW. The magnetic
fields do
not cancel exactly because they are not occupying same space.
Try this for fun: http://motionmountain.com/
Regards,
Boris Mohar
I see. In a typical electrical cord, there is a few distance in mm
between the 2 parallel wires with opposing magnetic field. So
not all magnetic field cancel as you say. Do you know of a drawing
or illustration in a site of the residue magnetic field produced
or an illustration of the graphics of the magnetic field being
in the act of being canceled. Thanks.
Dave
Generally it woiuld be the hot wire; the other one is at groundSuppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
If one wire has a leak to ground, the current after the leak is lower.
You can use a phase shift oscillator to get the 8 Hz sinewave. ThenJohn Miller wrote:
Dave wrote:
How can I create a 8Hz Sine Wave 220 volts signal. If
I convert the AC 220 volts to DC. Will I still get 220
volts? So what's the smallest circuit or device that
can make 8Hz sine wave out of the 220 volts DC. Thanks.
At how many amps?
--
John Miller
email domain: n4vu.com; username: jsm(@)
Surplus (For sale or trade):
Besson International Trumpet by Kanstul
Any amperage will do. I guess the steps I must take
is to put some diode to make the 220 volts 60 hz
becoming dc 220 volts. Then put some circuit to
make it produce 8Hz. Right?
What's the schematics of the circuit. As simple
as possible. Thanks.
D
Apologies.R.Lewis wrote:
"Dave" <davidqanta@yahoo.com> wrote in message
news:1116103520.136133.144900@g47g2000cwa.googlegroups.com...
Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
If the currents were not identical where the difference current go?
Radiated.
At what portion of the circuit does it have possibility of
radiating? The circuit is just composed of an electric
bulb and wires plug to AC. You mean the bulb radiate the
missing current as EM?
Dave
the currents would be the same even if it was radiated. as you said, the"Dave" <davidqanta@yahoo.com> wrote in message
news:1116109787.318838.325760@o13g2000cwo.googlegroups.com...
R.Lewis wrote:
"Dave" <davidqanta@yahoo.com> wrote in message
news:1116103520.136133.144900@g47g2000cwa.googlegroups.com...
Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
If the currents were not identical where the difference current go?
Radiated.
At what portion of the circuit does it have possibility of
radiating? The circuit is just composed of an electric
bulb and wires plug to AC. You mean the bulb radiate the
missing current as EM?
Dave
Apologies.
My response was rhetorical in that if the currents were not equal the
difference current must be radiated else there must be a mechanism to
'store' an infinite amount of current in your load (electric fan).
Since if the fan was left on a long time this would store all the
electrons
in the universe we would have a problem.
Since it isn't radiated the currents must be the same.
Nevertheless the current which flows into the fan is equal to the....
the currents would be the same even if it was radiated. as you said, the
electrons are not destroyed, so they have to be the same unless there is a
third path for them to get back to the source... such as a ground fault in
the device.
Not true generally.That doesn't happen to be true. The so-called flicker rate for the eye is
24 Hz.
60 Hz - I occaisionally see flicker.ANything faster than that is perceived to be steady light. Witness
the standard TV set with a frame rate of 30 Hz. (2 interlaced sets of video
at 60 Hz.). No flicker there that I can see, nor anybody else for that
matter.
Electrocution has nothing to do with choice of 50-60 Hz, since theseHigher frequencies have higher loss.
You body has more resistance to higher frequencies.
You eyes can perceive light flicker at 40 Hertz.
You nerve system runs at ~40 Hertz.
So low frequency is bad for lighting and electrocution. High frequencies are
bad for motors. Thus the compromise.
In most cases projectors expose each frame twice making the fundamental ofNot true generally.
I believe this figure comes from movies having 24 frames per second.
But with movies the dark period is short, the light period is long, and I
am told that projectors interrupt the light twice per frame to make the
flicker 48 Hz.
Try turning the brightness down, flicker is MUCH more apparent at high60 Hz - I occaisionally see flicker.
56 Hz - done by some monitors in 800x600 mode - I often see flicker.
My first tought was a RC-stage with a potmeter, feeding to the base of aHi,
How easy or hard it is to construct a kit that can
produce 12 volts with variable sine wave frequency
from 8Hz to 60Hz? Can I do it with only 6 components
or parts? I forgot many things in electronics so can't
construct complex kit.
Also if I have to extend the range to 5Khz to 5Mhz
using the same circuit wherein I can dial the sine
wave from 8Hz to 5Mhz. Is the circuit much more
complex than the first one.
Many thanks.
Dave
True.I believe this figure comes from movies having 24 frames per second.
But with movies the dark period is short, the light period is long, and I
am told that projectors interrupt the light twice per frame to make the
flicker 48 Hz.
75 Hz - I often see flicker (CRT screen).60 Hz - I occaisionally see flicker.
56 Hz - done by some monitors in 800x600 mode - I often see flicker.
It depends upon _where_you_measure_ the residual magnetic field....
I see. So if one wire has 10 mG, the second one has 10 mG opposite
in vector, because they are not in the same position in space, there
is a residual 0.8 mG left. ...
What about using a reflector?Then for a diameter of 25mm, you would only need a focal length of
40mm to get a spot diameter of 0.1mm. How are 40mm focal length, 25mm
diameter UV lenses pricewise?
The above question is partially meaningless- field at a point has no "shape"Don Kelly wrote:
"Dave" <davidqanta@yahoo.com> wrote in message
news:1116103520.136133.144900@g47g2000cwa.googlegroups.com...
Suppose you have 220 volts AC and a load such as an
electric fan. Is the current before and after the
load exactly 100% similar in value? Are there loads
wherein the current can become different before and
after the load. If they are all 100% exactly the
same. How come the two parallel electric cord glued
together commonly used in appliances still has residue
magnetic field (like 1.5mG) and they don't cancel 100%.
They theoretically should since the current before and
after the load is exactly the same so the magnetic field
is exactly 180 degrees out of phase so 0 mG output should
suppose to occur.
Thanks.
Dave
-The currents are the same. The reason that there is a residual field
is
because the two current "filaments" are not exactly in the same
location
with respect to anything beyond the wires. The field at a distance r
from
one wire is proportional to I/r while that due to the other is due to
I/(r+d) where d is the distance between the wires. Complete
cancellation
only occurs at points equidistant from both conductors.
--
Don Kelly
dhky@peeshaw.ca
remove the urine to answer
--------
I see. So if one wire has 10 mG, the second one has 10 mG opposite
in vector, because they are not in the same position in space, there
is a residual 0.8 mG left. Do you know a url that has illustration
what part of the waveform are cancelled and what part of the
waveform survives to create the 0.8 mG.
I wonder if the 0.8 mG left in the above configuration is 100%
the same in waveform shape, etc. than a single wire that emit
0.8 mG. What do you think?
Dave
-------------