May 13th, 2008, 01:11 AM
Why cant any website give a real definition of these? They always avoid the main question of, what exactly are these things. So, what are they? I want to know this in terms of the electrons and what they are doing.
Also, in a parallel circuit, the more resistors you add the lower the total resistance gets; why is this exactly?
More questions to come....
They are simply units/dimensions same as metres, seconds or kilograms.
Volts are a unit of potential difference (voltage) and are a measure of the amount of energy per unit charge. p.d.=E/q
Amps are a measure of current flow, which is the rate of change of charge in a circuit, having the instantaneous value of i=dq/dt. or for a constant (time invariant) signal i=q/t for any time interval.
Watts are a measure of electrical power. They can be given by P=vi, since power is the rate of change of energy, and:
v*i=(E/q)*(q/t)=Eq/qt=E/t
For the parallel circuit question, resistors in parallel share a common potential difference, since each one is connected atone end to the positive rail, and the other end to the negative rail (or ground). Crrent flows in each branch, and the total current flowing through the network is the sum of currents in each branch. By Ohm;s law, i=v/r, so if:
i<sub>total</sub>=i<sub>1</sub>+i<sub>2</sub>+i<sub>3</sub> + ...
and the voltage is the same across each branch, then:
V/r<sub>total</sub>=V/r<sub>1</sub> +V/r<sub>2</sub> +V/r<sub>3</sub> + ...
The voltages cancel, and you are left with
1/r<sub>total</sub>=1/r<sub>1</sub> +1/r<sub>2</sub> +1/r<sub>3</sub> + ...
So the resistance decreasing is a result of this equation.For a qualitative idea, the more branches you have, the more paths current has to flow.
This is probably best explained by analogy to water flowing in a pipe. In this analogy, the electrical charge, which is measured in coulombs, is like the volume of water. One coulomb is equal to 6.24E18 electrons. An ampere is 1 coulomb per second. If you have a wire that is carrying an ampere of current, there are 6.24E18 electrons flowing past any given point in the wire every second.
If you pump water up a hill to a different elevation, it gains energy. This energy is equal to the pressure difference from the lower to higher elevation, multiplied by the volume. Energy=Pressure * Volume. If you pump the water in a continuous stream, the power required is the energy per unit time, or Power = Pressure * Volume/time = Pressure * flow rate.
In our electrical analogy, voltage is like pressure, and flow rate is like current. Power, as measured in watts, is equal to Voltage *current, since current is a measurement of the flow rate of electrons. So one watt is equal to one volt multiplied by one ampere.
The reason electrical resistance goes down when you have parallel paths is the same reason the resistance in a piping system would go down if you add parallel flow paths.
May 13th, 2008, 08:45 PM
Volts are the pressure of electrons, trying to get to the opposite polarity pole. Amps are the intensity/induction of electrons in a flow caused by volts. That is why volts times amps equals watts.Originally Posted by Cold Fusion
It is the same as air pressure. If you know you have a certain air pressure, and you have a 3/8 line, you know how many cfm (cubic feet a minute). CFM would be the watts in the analogy.
Amps create more volume of electrons through intensity and because of ambient radiation, induction. The field around the wire gets larger as amps go up. That is how an amp meter works, by reading the induction field created by the higher voltage potential, created by the higher amperage.
Watts are the volts times amps, through what ever medium or device you are powering or flowing through, at the given ohms. Ohms limit volts and amps.
Ohms can change, upon the addition of higher or more voltage to a circuit.
There are different types of heating elements. Some heating elements are constant ohm heating elements, others are variable ohm heating elements.
The constant ohm heating elements tend to blow the fast acting fuses that should be used on heating circuits, quickly and effectively. The reason is that if you get a voltage increase. That can easily occur during the loss of a building neutral. The fast acting fuses will blow, due to an increase in amperage, due to an increase in voltage. This will protect the heaters the equipment and the circuits.
Induction motors will often only read a fraction of an ohm resistance when you place your ohm meter across the wires feeding the induction motor.
Sometimes it is because of a start winding engaged by the centrifugal start winding mechanism that disengages the start winding after a certain rpm is reached and the run winding can take over. Upon starting the start winding is engaged electrically. So you are reading the ohms of two circuits in parallel. Once started or with the start winding disengaged you only read the run windings.
Sometimes just the run windings that are the only windings in three phase motors, will show almost no ohms as well.
However once the motor is started, the momentary almost infinite draw of the magnet coil, is reduced by increased run ohms. Once the rotor lock situation is remedied by the motor spinning, and becoming in sync with the hertz that set the rpm. The ohms reduce. (Edited Ohms increase).
Some heaters actually lower (edited raise) in ohms as they heat up. They are usually marked with the start amperage that they will draw. However once they are heated you can check the amperage and it is often a fraction of the start amperage.
I wrote this program some years ago. You are welcome to use it and share it. It is really cool because you can enter in any two values and see how they effect the other two values, that are automatically given.
I saw one similar but it was not setup the way I wanted it. I sometimes create twenty occurrences of the program while I am working out something.
http://www.Rockwelder.com/Electricity/setupwir.exe
Sincerely,
William McCormick
You would do well to ignore everything Mr. McCormick has written. About the only thing he got right was volts times amps equals watts. CFM is not like watts, it is like amps. Amps are not induction. Ohms do not limit volts. When a motor gets up to speed the ohms do not reduce; the current does. You do not get a voltage increase when you turn on a heater.
Harold if you increase the pressure in a 3/8" air line, that will increase the CFM. Even though the ohms, or the restricting 3/8" line has not changed. In this scenario the amperage would change. Because the 3/8" line did not change.
If you increase the volts to a circuit with set ohms. The amperage will go up as well as the voltage, and that of course will increase the wattage.
Or in the analogy the CFM. Wattage is total throughput. CFM is total throughput.
This is because of intensity/induction in the wire. The wire literally expands. There is a field around the wire that grows. An induction field. It inducts electrons into the wire from ambient radiation. And intensifies the flow. With a wider and wider field of induction.
What in particular do you not agree with?
Sincerely,
William McCormick
I agree with you
I am going to venture that you will not dispute a single thing I wrote and corrected last night. I just switched up two terms. A cut and paste error. You can see that the rest of the post explains what I meant.I agree with you
I used to manufacture three phase heating equipment. So I have some experience in it.
That is exactly how it is. Therefore for whatever reason you dispute it, you will be fighting reality.
I only have to fight unreality.
Sincerely,
William McCormick
Why would i bother enquiring into parts of what you wrote.
I have asked questions in other topics about thigsn you said but you fail to give answers, I just agree that people should ignore everything you say.
Its funny that I understand quantum theory yet do not understand electric circuits so well.
I am curious about the usage of watts because the audio industry mainly uses it to describe the volume output of its equipment. Wouldn't it be more useful to use amps instead? (As in, this is a 6 amp speaker)
Thanks for the EQ's and definitions.
My physics teacher used the water/ pipe example, but I see problems with it. Doubling the number of signal paths does not reduce the resistance considerably. Having two resistors instead of one would only appear to lighten the load per resistor, and divide the work in two, which would still allow you to come out with the same resistance. There must be something else to it.
I found a website that seems to make sense of this. Can you verify its accuracy?
http://www.eskimo.com/~billb/miscon/voltage.html
If you increase the voltage, are you also increasing the speed of the electrons? (I heard this once)
Why is it that by having a very high voltage in power lines, you are creating less resistance than one with a lower voltage?
Why does AC cause less resistance than DC?
Yes, but you said cfm would be the watts in the analogy. It's not. Watts is a unit of power. CFM is a measurement of flow rate. To get energy you would have to multiply the CFM by the pressure.
No, not unless it heat up, and that would only be thermal expansion.This is because of intensity/induction in the wire. The wire literally expands.Where did you get this bizarre idea? The wire is already full of electrons. The ambient radiation does not have electrons in it. How many times do you have to be told that?There is a field around the wire that grows. An induction field. It inducts electrons into the wire from ambient radiation.
Harold when you talk about watts. You are talking about a load. I would agree with you that in an open circuit a resistor will not lower volts.
However under a load, the volts are lowered and this causes the amps to lower. As well. Volts control amps.
Let me give you a real example. I have a large elemental resistor. It has 38.4 ohms, resistance across its leads. It is feed from a 480 volt power supply. So each of its leads are receiving 480 volts. It will draw 12.5 amps and output 6000 watts of heat.
Now I add in another identical resistor in series. It would be the same as adjusting a rheostat to control a heating load. Except it is simpler and more clear to just add in another resistor.
When I add in this second identical resistor into the circuit. The total load will be 3000 watts, at 480 volts, at 6.25 amps, and the ohms created will be 76.8 ohms.
But that means now that each resistor/heater is receiving 240 volts, across its leads, each heater has a resistance of 38.4 ohms each. Each heater is pulling 6.25 amps each, and outputting 1500 watts each.
So by adding a resistor or increasing the resistance you lower the voltage.
If one of the those resistors was a constant ohm heater, you can see how it would cut the volts in half to the heater.
Sincerely,
William McCormick
Where is this mythical question?
Sincerely,
William McCormick
Cubic feet a minute of air is measured at sea level atmospheric pressure.Yes, but you said cfm would be the watts in the analogy. It's not. Watts is a unit of power. CFM is a measurement of flow rate. To get energy you would have to multiply the CFM by the pressure.
No, not unless it heat up, and that would only be thermal expansion.This is because of intensity/induction in the wire. The wire literally expands.Where did you get this bizarre idea? The wire is already full of electrons. The ambient radiation does not have electrons in it. How many times do you have to be told that?There is a field around the wire that grows. An induction field. It inducts electrons into the wire from ambient radiation.
So when you increase pressure in a 3/8" air line. You get more atoms of air per linear section/unit lenth of air line.
That means that with the higher pressure, it is going to move air faster. That is accounted for in the pressure part of the formula.
But you also get an increase in intensity due to compaction of molecules of air. So that each linear inch of air in the 3/8" air line, that passes through the outlet, will carry a higher intensity of air atoms with it. At whatever the velocity caused by pressure.
That intensity or compaction caused by pressure/volts in electricity, is the amperage. Amperage is the density of electrons in the wire.
Watts tells the whole story of volts, pressure/velocity, and amps intensity/induction.
I would not make this stuff up.
If there was no intensity there would be no need for amps in the formula.
Sincerely,
William McCormick
When it gets converted into sound, the loudness of the speakers will be related more to the power in watts.Think what happens when you have a 100 watt electric lamp plugged into an outlet. Now plug a second 100 watt lamp into the same outlet. You have just added a resistor in parallel. The power did not change in the first lamp. You now have a 200 watt load. The current is twice what it was with one lamp plugged in because the resistance is half.My physics teacher used the water/ pipe example, but I see problems with it. Doubling the number of signal paths does not reduce the resistance considerably. Having two resistors instead of one would only appear to lighten the load per resistor, and divide the work in two, which would still allow you to come out with the same resistance. There must be something else to it.
It seems accurate but doesn't appear to me to simplify matters very much. If it works for you, great.I found a website that seems to make sense of this. Can you verify its accuracy?
All else being equal, I guess that's true. The current goes up, which means more electrons are going through a section of the wire each second, so I suppose that means the electrons are moving faster.If you increase the voltage, are you also increasing the speed of the electrons? (I heard this once)You don't have less resistance in the wire, but you do have less line losses due to the resistance. This is because the power is equal to voltage multiplied by current, so a high voltage can have a lower current for the same power. Lower current through the same resistance means less power dissipated in the resistance.
Why is it that by having a very high voltage in power lines, you are creating less resistance than one with a lower voltage?
Why does AC cause less resistance than DC?
A-c does not cause less resistance than d-c. Perhaps what you are referring to is the fact that d-c cannot easily be transformed to a high voltage for transmission. The lower voltage translates to higher transmission line loss, as I explained above.
I found the post, I did not refuse to answer it, I just did not see it, or saw it, and forgot to reply to it.
I answered it now.
Sincerely,
William McCormick
Here is a table of electrical symbols from the telephone company.
Sincerely,
William McCormick
Why does the current increase when you decrease the resistance, and vice versa?
I read that without resistance between the anode and cathode, no current will flow. Why?
I thought about the fact that a higher voltage lessens resistance. You could make this analogy: There are 5 lanes. Either you can have 4 cars traveling at 50, or 2 at 100. Every lane has cars opposing it from the opposite direction. Normally, either resistance would be equal...but it is not. Is this due to a type of thermal/electromagnetic threshold limit that the material inherently possesses? This would prevent the speed of the electrons from generating as much resistance due to the density of its effect per cubic mm.
The pipe example would work if you were talking about an actual resistance due to size constraints. I believe wire wound resistors work this way. Due to their diameter the energy is forced into becoming heat due to (possibly) an electron per mm^3 limit that exists. This is like a pipe, in which case the pipe example makes sense. But what about the other sorts of resistors like carbon based resistors?
The teacher was supposed to have used the garden hose. Because it expands a bit as you increase the pressure. An electrical wire although it does not physically expand. Its inductance field expands. Intensifying the amount of electrons in the wire. The wire picks up more electrons from ambient radiation that would have just passed through the wire undetected.
Because as you increase intensity, it is harder and harder for the ambient radiation to pass through the wire. Ambient radiation starts to slow and turn away from the most abundant part of the wire towards the less abundant part of the wire.
The wire actually looks like a continuous funnel, diverting ambient radiation that would have passed right through the wire at a perpendicular angle to the wires length. Undetected, leaving no effect.
This ambient radiation is now turned slightly away from the abundant with electron terminal, and towards the short of electron terminal. All the way along the wire.
This is what you read with the amp meter. The inductance field.
Intensity is the actual intensity of electrons in the wire. There could be a difference.
In a speaker output there is usually 8 ohms of resistance expected. If you raise the voltage in order to raise the amperage, you may reduce the effect of ohms with voltage for split seconds before the magnetic coils create resistance.
But for instance if you have a 6 amp speaker being feed through 8 ohms of resistance. The most you can get is 288 watts at 48 volts. Unless you incorporate other tricks of perpetual motion/capacitance.
To get 1000 watts you need more voltage, and then you can even have more ohms because the volts will offset the ohms.
You could pump 100 volts into a ten amp speaker through ten ohms of resistance and come up with 1000 watts.
Or you could use a circuit with less ohms and pump more amps. At 1.25019998400256 volts through a circuit with 0.001563 ohms, you could put 799.87203071181 amps to the speaker, and deliver 1000 watts. Of course this is probably out of the range of the logistics of car speakers and equipment.
But as I said with resistors or capacitors you can create tricks that give you power beyond what you feed the speakers.
My calculator is extremely accurate, however if you do not calculate for attenuation of long lengths of wire, capacitors in series or other such oddities, it will not work.
Sincerely,
William McCormick
Resistance/insulator work the same way. They stop or slow the flow of electrons, by actually quickly polarizing on the surface. Almost like light hitting a surface, and making it shine, and yet not penetrating it, apparently.
As you charge an insulators surface like the coating on a wire, with a conductor it is shielding. The insulator raises in voltage very quickly and then just repels the electrons in the conductor. Or if the conductor is short of electrons, it repels the outside airs abundance with electrons, by raising quickly in voltage on the outside of the insulator.
A resistor does something similar, it raises in voltage more quickly then the wire it is being fed by and feeding to. So that electrons flowing into the resistor are slowed by an abundance of electrons in the resistor. Kind of like a light bulb.
As Harold pointed out in open air, you can get whacked with the full voltage. Even from a highly resisted or insulated circuit unless the resistor is stronger then the air in the area, and the resistor can drain off into the air.
Sometimes a very high voltage device with minimal amperage is overlooked and suddenly it is allowed a place, an object or device to store this voltage, and next thing you know, someone is very surprised or shaken up. Could even kill you.
I was reading that carbon can actually lower in ohms upon heating.
Sincerely,
William McCormick
Here is something that will open up a can of worms and get me in all kinds of off topic trouble. Ha-ha.
But you do have to understand this aspect of it.
Amps do have some other qualities. If you ever boxed or even hit a punching bag. You realize that it takes little actual power to just get your fist to the bag. And if you get good, you can get your fist to the bag before your partner even can block it.
Once at the bag, you turn up the power and drive it home, almost the Bruce Lee one inch punch trick.
My point is that voltage gets the electrons there quick. However the low ohms in the supply lines that allow for high amperage flow, keep the power coming as long as the amps are available. We often see things spark or ARC out and say wow that was scary but not that bad.
Many do not know that our power to our house is not the power inside the house. The reason is a small piece of ribbon that feeds copper shoes in a circuit breaker. This ribbon limits voltage and amperage. That is why when we turn on induction motors we do not brown out our neighbors houses.
Take away this ribbon from the breaker and some induction devices could take a transformer off the pole. Under the right conditions.
My point is that if you have some voltage, low ohms and a power supply that will deliver many amps of power. The voltage even when low, will flow with amazing power and distance. Especially over a heated air gap.
Take a look at this
You can see that the ARC that is created at two places on that wire is instead of radiating as it would from an ARC rod, that has that same polarity, as the arcing pieces of copper throwing sparks, also the same polarity as a current cathode. It is being blown back against itself. It is being blown by electron pressure from the torch on the right.
The torch on the right is abundant with electron pressure. The other side of the wire is short of electrons. I have a couple hundred amps feeding the water cooled torch.
And you can see the electrons blow the wire and the molten copper away from the torch.
My big problem is that Benjamin Franklin called the torch in that animation, the positive terminal, and he did. It was called the positive terminal until colleges meddled with it and confused it thoroughly. They even mislabeled batteries.
On the machine supplying the power in that animation, the torch has the polarity called straight polarity, because it comes straight out of the torch. The other setting on the machine that reverses the flow of current is called reverse polarity. Because the electrons would flow to the torch in this setting.
Just some more stuff to gauge the importance of amperage, voltage and ohms with.
That is showing although the voltage may be higher on the Arcing piece of metal. That creates a cathode at the surface. And Cathode rays. That amps can outdo volts. And force the higher voltage low amperage energy back. As long as the amperage is there.
Sincerely,
William McCormick
It is really by definition. The formula is I=V/R. If the voltage is constant and you increase the resistance, the denominator increases and the number is smaller. The very name "resistance" implies that it will resist the flow of current.
That is not really accurate. If you have a battery with nothing connected between the anode and cathode, no current will flow. That is because the resistance of the air between is infinite, or nearly so.I read that without resistance between the anode and cathode, no current will flow. Why?
No, it doesn't work that way with electricity. As you increase the voltage, more "cars" will flow. There really isn't a limit unless you melt the conductor or burn it up, then the resistance increases, not decreases. The higher voltage does not lessen the resistance, unless you are talking about something like lightning or an arcing fault where the insulating material breaks down. But for most purposes, you can consider the resistance to be constant, i.e., it is a linear relationship between voltage and current. Learn and understand that before you move on to more exotic stuff.I thought about the fact that a higher voltage lessens resistance. You could make this analogy: There are 5 lanes. Either you can have 4 cars traveling at 50, or 2 at 100.
All materials are like that wire wound resistor in that as you increase their length or decrease the cross-sectional area, the resistance increases. It is just that different materials have different conductivity. Maybe you could think of it as a pipe filled with sand or some other porous material.The pipe example would work if you were talking about an actual resistance due to size constraints. I believe wire wound resistors work this way. Due to their diameter the energy is forced into becoming heat due to (possibly) an electron per mm^3 limit that exists. This is like a pipe, in which case the pipe example makes sense. But what about the other sorts of resistors like carbon based resistors?
I do not believe that it would take much to create a diode capacitor ladder, to raise AC voltage to DC voltage.
High voltage DC current could prove to be very dangerous. Because once high voltage, DC started to ARC or beam to the ground, or other objects through air, It might not stop.
That is why AC current is probably used for high voltage power lines.
AC current will often break an ARC when it is happening through air. Even over a short distance.
Sincerely,
William McCormick
If you looked at my heater post or message.It is really by definition. The formula is I=V/R. If the voltage is constant and you increase the resistance, the denominator increases and the number is smaller. The very name "resistance" implies that it will resist the flow of current.
You might have seen that when I put two identical heaters in series. I doubled the ohms, and I halved the voltage. At the junction of the two heaters.
That means that in the center of the resistor if I half the ohms of the resistor, I will have double the voltage there in the center of the resistor.
It is really the volts that effect the amperage.
By halving the ohms you are raising the potential of the volts, to carry electrons across the resistor with more pressure.
Here are some formulas to look at it in other ways.
Volts (Electron Pressure) EMF (Electron motive force) (Electron potential)
Volts = Square root of Watts times ohms
Volts = Watts divided by amps
Volts = Amps times ohms
Amps (Intensity/Induction)
Amps = volts divided ohms
Amps = Square root of Watts divided by ohms
Amps = Watts divided by volts
Ohms (resistance)
Ohms =Volts divided by amps
Ohms =Watts divided by amps^2
Ohms = Volts^2 divided by Watts
Watts (or power)
Watts =Volts^2 divided by ohms
Watts =Amps^2 divided by ohms
Watts =Volts time amps
Although watts is a total picture of power. Watts alone is rather useless in seeing a whole picture of what is taking place, without one other value.
Sincerely,
William McCormick
CFM is a unit of power. It relates directly with known equipment to watts.
In other words with standard equipment using standard principles and no perpetual motion, or velocity tricks. CFM is the power required and output.
Just like Watts is the total power output. However in both cases you need at least one other variable to see what is happening.
You could output 22 cfm through a 40 inch pipe at under one pound of pressure per square inch.
You could also use over 100 pounds per square inch to push 22 CFM through a 1/8" pipe.
The same is true of electricity. Watts just represent the total combined volts and amps at some unknown ohms.
To get a picture you need at least one of the other three variables. The others you can fill in with formulas.
Sincerely,
William McCormick
1 ampere = 6E18 electrons per second.
volt is the push on these electrons, ohm is the drag.
imagine this is a cable.
the grey balls are electrons, following the blue track, which is the cable.
each ball represents several gazillions of electrons in reality, but the concept is basically the same. if one ball moves, all the balls move.
they do not move constantly in one direction however.
they move a little bit forward, and a little bit back., sort of like the waves on a beach.
DC only uses the power of the forward movement, while AC uses the energy of the electrons moving both ways.
1 ampere = 6E18 electrons per second.
volt is the push on these electrons, ohm is the drag.
imagine this is a cable.
the grey balls are electrons, following the blue track, which is the cable.
each ball represents several gazillions of electrons in reality, but the concept is basically the same. if one ball moves, all the balls move.
they do not move constantly in one direction however.
they move a little bit forward, and a little bit back., sort of like the waves on a beach.
DC only uses the power of the forward movement, while AC uses the energy of the electrons moving both ways.
Attenuation of wire, shows that to be a wrong theory. Capacitance of a long piece of wire in open air, shows that to be a wrong theory.
However for a simplistic look, or to explain one point of view it may be useful.
What really takes place though is what I said. Ambient radiation is diverted, away from the abundant with electron portion of a loop. And towards the less abundant with electron portion of the loop.
Basically away from one side of the ambient radiation diode (battery, charged capacitor, generator), and towards the other side of the diode through the loop.
So the ambient radiation really just fills up the wire with free electrons. And keeps it charged ready to go. When you increase voltage even through the same wire and ohms, you get an intensity in the electrons. In the wire.
As if your balls grew, or became more dense. So you have two factors, to contend with. You have the higher pressure or voltage, that means more linear movement of any one of your balls over a given time.
And you also have increased intensity of compaction of space between the electrons. That means that each one of your balls will carry more electrons in it. That is amps. We measure this intensity in the wire by the effect it causes in the ambient radiation field (Induction field) around the wire, with an ammeter or amp meter.
There is a difference in intensity though. The formulas I posted, or that calculator I posted is great for showing the ratios.
A circuit is fed 10 volts through one ohm, it draws 10 amps and uses a total of 100 watts.
The same circuit is fed 11 volts through one ohm, it draws 11 amps, and uses 121 watts.
Notice the total power put through the wire. It is more then just the amps or volts. The slight change in voltage and amperage causes the change in total throughput to multiply.
Watts show you what the amps and volts are doing with total throughput.
Watts is a measure of power, however it is also a measure of throughput of electrons in a circuit.
Sincerely,
William McCormick
I was just re-reading the previous post, and I think I see why kids never learned this. All the big balls, and growing balls. Never would have worked in a classroom. Ha-ha
Sincerely,
William McCormick
.....electricity is so interesting.
This was a double post.
The Grumman guys could do anything with electricity. Some things they did were just too funny.
They are at home in a Testla ARC. Magnetism was just a tool.
This device below took magnetic electrical energy and pressed aluminum up against a reusable cold mold. This was done in the seventies.
Here is the Rigel Ram Jet rocket they built in the fifties. This technology was already obsolete at the time. That is why often we did not promote the work we were doing even if it was ahead of its time. It was still wrong. But paid the bills.
We stated it as such. You will note a huge amount of humility from Grumman engineers for these reasons. Even the Lunar module, was built by guys that knew there was much better available at that time. But that is all that was allowed.
http://www.Rockwelder.com/military/Rigel.htm
One of those links will take you to the actual museum link.
Sincerely,
William McCormick
Using this information, I tried to make an LED circuit form this: http://www.radioshack.com/product/in...t&tab=features
I used 2 1.5 volt batteries wired in series, with 5 1500 ohm resistors wired in parallel. 10 mili amps. The light was not bright at all, and could only project onto the ceiling at night with all the lights off. Did I do something wrong, or was it a bad LED? I also tried using 6 volts, 20 mili amps, but the brightness never increased. Even when I hooked up a 4.7 ohm resistor that I found, which equates to 638 mili amps, it still did not get any brighter. I eventually went all out and hooked up a 9v with the 4.7 ohm resistor, almost 2 amps; it instantly burned it out, causing a pleasant burning smell. Another thing, are you meant to compensate for the voltage drop across the resistor? I tried calculating it as many times as I could, but while factoring in voltage drop, the led never could get enough volts. Maybe I am misunderstanding the voltage drop process?
You are forgetting about the voltage drop across the LED which is about 2 volts, and that only leaves 1 volt through your resistor network. Your five 1500 ohm resistors in parallel would give you 1/(1/1500+1/1500+1/1500+1/15001/1500) which is 300 ohms. 1 volt /300 ohms is equal to 3.3 milliamps, not 10 millliamps. The 6 volt battery should have been brighter though. That would be 4/300 = 13 milliamps.
I gather that you are just calculating the numbers and not checking with a voltmeter. You should really get a digital multimeter. They are about $20 but they come in really handy if you are going to work with anything electronic or electrical.
These physical units of volt , ampere and watt are essentially different multidimensional space time , they can finally be defined by their nature of space time structure .
For ampere , A = √|G| m^3 s^-3
that is , one ampere is consists of 3 dimensional space , minus 3 dimensional time and an coefficient √|G| .
For Volt , V = √|G| m^2 s^-2
that is , one volt is consists of 2 dimensional space , minus 2 dimensional time and an coefficient √|G| .
For watt , watt = |G| m^5 s^-5
that is , one watt is consists of 5 dimensional space , minus 5 dimensional time and an coefficient |G| .
here , |G|=6.67259e-11 (modulus of gravitational constant)
These three physical units are substantiated form of multidimensional
space time in our materizlized world .
Objectively , every physical unit has its own space time structure and can be universally expressed by an formula as :
dimA = Bm^a s^-b .
here , dimA is an certain physical unit , B is coefficient ,
a , b is whole number and its value is less than or equal to 5 .
Since the universe is composed of various physical quantities (physical units ) , so the universe also is consists of 5 dimensional space and 5 dimensional time . In other word , the universe is of 10 dimensional space time .
You can get an overall picture about multidimensional space time characters of physical units common used at :
http://www.universefedback.com/popularized_e/c2.htm
http://www.universefedback.com/popularized_e/c3.htm
http://www.universefedback.com/popularized_e/c1.htm
What? (Directed towards zhang zhi qiang)
So there is a voltage drop across the LED.....do you not need resistance to create a voltage drop? I used a DMM to try to measure the LED's resistance-it came up with 0.
Are the voltage drops across LED's all the same? If not, how do I calculate it?
So, you cannot consider the LED a source of current draw, even though it has the resistance to create a voltage drop? :? I'm lost.
A diode is kind of like a resistor, but it is not linear. Take a look at the characteristic curve shown on this page
http://www.kpsec.freeuk.com/components/diode.htm
The current is zero up until a threshold voltage, which is called the forward voltage drop, then it suddenly shoots up. A resistor's characteristic curve would just be a straight line from 0 volts, 0 current to any point on the curve.
No they are not the same. The catalog sheet you linked to in your first post tells you what your diode voltage is. I think it said between 1.9 and 2.2 volts.Are the voltage drops across LED's all the same? If not, how do I calculate it?
For purposes of designing your circuit, you can think of it as a 2 volt battery connected in the opposite polarity to your battery. But that's only true if your battery voltage exceeds the diode's forward voltage drop.So, you cannot consider the LED a source of current draw, even though it has the resistance to create a voltage drop? :? I'm lost.
I found that you do not need much amperage to power many LED's. In some cases you could probably power them with a rather high ohm resistor.
They get dim with too much amperage. I was feeding some with a resistor and they worked nicely. The voltage was just a little below the battery output.
But when I hooked them up direct they got dim and blew.
You could just get a set pot, a couple more batteries and look at the actual ratios. You might spend four dollars at Radio Shack.
You would need a voltmeter and an inline amp meter would be nice, to record your different settings when you find the optimum voltage and amperage.
Sincerely,
William McCormick
http://www.use-enco.com/CGI/INPDFF?P...1036&PMCTLG=00
These are some inexpensive meters that are OK.
I have a problem with all the meters and all the meter companies.
They often all show different things or do the same thing in different ways.
But these are ok to fool around and experiment with.
I use this brand another model to work on high voltage HVAC equipment. Really big stuff.
And it works well. It like all meters have issues.
Most servicemen want a setting for an audible indication of whether a circuit is open or closed.
Located on the main dial.
Very good to check out low voltage thermostat wiring.
You do not want to look away from what you are doing to read the meter,
because the system is usually live.
You just cannot shut down huge systems at hospitals like Sloan Kettering.
You have to work on them live.
The meter I have has this option, but you have to press another option
button once you are in the ohms setting. Can be a pain in butt.
Mine has a backlight which you can turn on, very nice to have.
It also auto off's that is nice.
The next one I want to get is the one with the laser temperature probe.
This way you do not have to get up to a supply register to stick your
thermometer into the register, to do a TD (temperature differential).
Often in commercial work you need a step ladder, that is out on a truck two blocks over.
With that meter, you can just shine your laser up there.
On most current systems the TD is 22 degrees, optimally.
From return grill inlet temperature to the supply register temperature.
But those are nice meters for testing.
You have to watch though many of them now are RMS. Root mean square.
That means that you might actually have 400 volts AC current or DC
pulse with meter in AC mode, and it will only register 90 volts.
Because of the "Root Mean Square" conversion the meter does.
And square wave, although no peak is over 100 volts will register in at over 130 volts.
When I do testing I often use an oscilloscope. I will even bring one to job sites.
http://www.Rockwelder.com/Electricit...squarewave.wmv
Be careful when working with 110 volt house current and electronics,
because its peaks in my area are actually 166 volts above and then below neutral.
The root mean square of that is 121-130 volts depending on the meter you use.
You can get some sweet oscilloscopes from Techtronics for pennies
on the dollar of what they cost just a few years ago.
And unless you are working on satellite de scrambling they will be way to
much for the extreme electronics guy.
Just wanted to add that today there are root mean square meters and True root mean square meters. You have to be careful when using them. Either way.
Sincerely,
William McCormick
One thing you never want to do. Is hold the meter in your hand while you are testing. I worked with a fellow, that did not get my lesson from my father.
He was up on a roof, checking out a gas fired system. When he just touched the natural gas ignition wire that fires the gas for the heat exchanger in the unit. He was shocked rather violently right through the meter. He was probably lucky to be alive.
The reason why you have to be careful is capacitance. You can become the plate in a capacitor.
When you see white light you are looking at 30,000 volts potential. If you let it reach full capacity in test equipment, and you are on the other side of the test equipment look out.
I was taught a rule for checking circuits and using meters as a small boy. When I got my first Simpson meter, that I believe my Aunt Henny brought home from Grumman for her husband Uncle Ernie a small appliance repairmen, who gave it to me.
Wow it was a beauty. My father quickly laid down the rules for using it. He said that while checking circuits to put the meter on a grounded surface or the ground. Hold one test lead in your hand preferably with an alligator clip and attach it and let it go. Take your last lead and go around and test.
A couple years ago I got to work just after a holiday, and the boss said all the power was out. So I grabbed the meter I only use for volts and off I go. I go down in the dark, with just a little flashlight. I put down the meter, I connected the one lead with the alligator clip and then touched the other main.
To my surprise, I saw light. Tremendous light. The test leads were as big as fluorescent bulbs and brighter. I felt like someone really big smacked me in the head. But I was alive.
I had forgotten just before vacation I had set the meter up to check an Allen Bradley panel light to see how many milliampere they draw.
Wow, I will never do that again. The test leads were just giant rubber bands. Not a drop of copper in them. Not a gram. I came up with the test leads bobbing up and down. It was just too funny.
I forgot the most important rule about using electrical meters. Never pick up someone else's meter or loan yours out without checking. Check the fuse inside. To see if someone put something other then a fuse into the fuse holder. This meter was jumped out with a brass welding rod.
And my memory on this is poor. However I remember at one time we were checking something low voltage out, and found that the meter was blown. So we stuck a piece of brass welding rod in just to check the battery powered device. But I do not remember how or why I forgot to take it out or check it later. To be honest I do not really remember if it was that meter or not.
We have about twenty meters.
Sincerely,
William McCormick
William,
You stuck a piece of welding rod in the meter in place of the fuse. Then you used the meter on milliamps range without checking before you connected it to high voltage. And they still let you play with electricity?
You should try my world for a week or two. It turned out, it was the power company, they dropped a three phase leg. When the guy came he was holding his meter, in his hand and I explained what could happen. He agreed. All the lights were on two legs in the shop, one of them went out.
Even with the fuse, if you have a transformer blow, while you are testing, you could experience the same thing.
Yes, I work with all kinds of electrical equipment. When I am doing an actual job for a customer I am actually Mr. Unger or Mr. Perfect. All my stuff is neat and tidy. In fact that meter was my shop in house bang it up meter. I have much better stuff for the road.
I used to install remote satellite controlled heating and cooling controls. In large heating and cooling systems. Everything from rack to Mammoth rooftop units. I just did it for the fun and love of electrical equipment. I used to design the bypass circuits and add relays to take control of the system via satellite link.
Once up on a rooftop, two guys I was with went up with the head mechanical engineer on site. And the guy told them to watch out for the pigeon zappers. I get up there a few minutes later all ready to go. And my partner says, can you see which room this unit feeds. So I look over the parapet wall, up about five stories up, and put my hands on the parapit wall. I get the pigeon zapper. When I pulled off, the white ARC followed my hands up almost four inches before it sputtered out. I turned around and he was on the ground laughing. We are a rough bunch.
The brass rod in the meter was one of those things what was supposed to get replaced immediately. But we probably got to talking and never got another fuse. Lord knows we do have enough of them.
It is the way things are. If you want to get a lot done, you are bound to run into some of these kinds of things. But basic safety keeps us safe.
We were probably trying to do a favor for someone, and just rigged the volt meter, so we could fix his device.
I have been using a meter safely for many years. Never been shocked yet. Blasted once but not shocked. I know a couple guys have gotten blasted through their meters. Because they hold them in their hand.
Bet you do not do that.
You can also get a new meter that has a screw loose, a drop of solder connecting two terminals, or drop the meter and a screw comes loose inside, and this screw can do the same thing as the jumper I put in. That is why I just follow meter safety. You will live through it holding just one electrode.
There was a guy at Grumman that used a pencil to get something out of a circuit board he was killed.
In prison they use a piece of pencil graphite tied to a piece of toilet paper. They tie the other end of the toilet paper on a stick, a stick that they have to turn on or off the TV. They first pull the plug of the TV out just enough to allow the pencil lead to hit both prongs of the brass plug. The graphite ARC's, the toilet paper lights and they smoke a smuggled joint.
Sometimes they just use a few strands of copper wire from the earphone wires and a battery.
Need a laugh check out these?
http://video.google.com/videoplay?do...42195661364567
http://video.google.com/videoplay?do...BJK8rwKGk6zjCg
Story of my life.
http://www.Rockwelder.com/funny/MPGfun.wmv
Alright I am not always serious on the job.
I would call the guys out in California when we wired in the Satellite control systems. And I would talk to them on a i870 Motorola phone. It looked like the Star Trek communicator. Well to make it worse, the two guys in the office that I would three way and trouble shoot with, were named Kirk and Scott. I thought I had reached the Twighlight Zone.
It just does not look right talking into one of those phones and saying Scott I am not getting power. Kirk what should I do? I am sure some people after seeing me think I am stranger then I am.
When we were wired in. They would send us, or the units a Satellite Packet and they would, in a matter of three seconds shut off as many as eight unites one right after the other. From out in California. The noise of shutting down eight rather large units like that is pretty haunting or eerie. Especially when it is being done, more then a thousand miles away.
But this company is able to save the customers thousands a month at each site, because of the special ramping system they use. And other techniques for preventing waste. Some companies hire their guys full time at their headquarters.
They can tell what is wrong with the system from out in California. They caught a mistake in a poorly wired system. That nearly blew the Freon out the water cooled condenser. Just by their computer picking up temperature ranges that were not correct.
Sincerely,
William McCormick
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