I know next to nothing about electrical and electronic technology, and when I try to read over the skill descriptions for Tech levels nine and ten I find myself crossing my eyes to make the words form interesting designs. I can understand what each skill is, while I'm looking at it, but I absolutely fail at trying to extrapolate from what it is to what can be done with it.
Is there any way, aside from biting the bullet and doing the research, that I can tell with reasonable expedience which electrical applications and devices are possible under a bias of, say, T9@4 and which are not?
Two year technical degree in electronics.
T9@4 Sound and Pressure Electrical Generation
T9@4 Sound Transmission and Reproduction
T9@4 Electric Motors
This would be, in order, microphones, speakers, and motors. So, if you cannot do these, you could not electrically record, electrically play, or use any electric motor systems.
Basically, your tape deck is now a paperweight.
I just woke up, that might not be too clear, let me try again.
Microphones change sound into electrical impulses.
Speakers change electrical impulses into sound.
Indeed, you can hook a light bulb up to a speaker wire and the light bulb will flash in time with the sound the speaker is making. It's a pretty cool parlor trick if done properly.
Electric motors, I would think that would be obvious.
The tape deck you were using to record and listen to nature sounds in your last world? It uses all of these components, and if they are curved out, is now junk.
T9@4 Sound and Pressure Electrical Generation
You know a push button cigarette lighter? It uses something called a (sp) Piezo electric crystal to generate the spark the lights the lighter. The crystal is pressure sensitive and generates a spark of electricity when placed under pressure. So your Zippo will still work, but your push button lighter won't. Anything which generates electricity through sound or pressure. Think of a microphone as being an electric generator that is run by the sound of your voice.
T9@4 Sound Transmission and Reproduction
Telephones, speakers, anything which plays sound.
T9@4 Electric Motors
The starter in most modern cars is an electric motor. That is powered by the battery to start the gasoline engine, and disengages itself once it does so. The gasoline engine might still work (I haven't read that far yet) but the starter wouldn't. You would have to light up the gasoline engine by some other means.
Does any of this help?
Oh yeah, and just to be clear, a motor takes its power from a source outside itself (IE a battery, or some other power source) an engine generates its own power through (typically) combustion of fuel. If it is externally powered, it is a motor, if it is self-powered, it is an engine.
Does any of this help?
It's all golden. Thank you, this is exactly what I want: the gizmos and widgets that these skills make possible.
So, from the other side - if we're saying the bias is T9@4, what can't I make given that I don't have access to transformers, capacitors, or inducters (all T9@5)?
I just realized, this is talking about electrical, not electronics. The first is the power lines and wiring up to the outlet, the later is from the outlet out.
Electrical transformers use electricity inside magnetic coils to step the voltage up or down. If I recall, the trade-off is that it steps the electrical current in the opposite direction from the voltage. Compare it to running water through a 1 inch pipe, and then through a 4 inch pipe. Larger pipe can handle more water volume (greater voltage) but the same amount of water won't be under as much pressure (lower current) Does that make sense? That would mean that if they had the capability of generating electrical power, it would come to your house at the same voltage it was generated at, because it can't be stepped down.
Capacitors are like rechargeable batteries. If you've ever had a piece of electrical equipment that was unplugged turn on or otherwise activate in some fashion for a moment or two, that was the capacitors discharging. They're often used with transformers to help in stepping the electrical current up or down, and to help switch it from Alternating current to Direct current.
Electrical inductors, I'll be honest, I don't have much recollection of what those do.
I think what all of this means, in a nutshell, is that you could not have a centralized electrical power grid. No electricity running through wires into your house.
Glad to be of help Scott. I figure I owe you a few for all the questions you've answered for me.
Thomas Edison and Nikola Tesla were rivals. Edison was heavy into Direct current, Tesla was heavy into Alternating current. Direct current runs in one direction, it's the kind of power you get from batteries and AC adapters. Edison tried to power a city with direct current, but found out that direct current couldn't be transmitted long distances and keep up the voltage. Alternating current does not have that problem. Direct current is generally not as powerful, but is safer. So I guess this also means that you could not have any AC to DC conversions.
Yes, the water-in-pipes analogy is crystal clear.
So, without transformers, electrical power needs to be generated on location and at exactly the voltage required? That sounds limiting.
Here's a question that shows off how little I know: for what things do you need high voltage, and for what things do you need high current? And, how do you control how much of each you're generating?
Edit: Oh, gosh, no AC adapters? I have like five of those in every overnight bag I pack . . .
So, without transformers, electrical power needs to be generated on location and at exactly the voltage required? That sounds limiting.
Pretty much, yeah.
Here's a question that shows off how little I know: for what things do you need high voltage, and for what things do you need high current? And, how do you control how much of each you're generating?
Do you know what a Vandegraph Generator is? They have one at the science museum here in Columbus. You put your hand on it, and it sends a static charge through your body, which makes your hair stand on end. What it does is give your body a negative electrical charge, like charges repel (think pushing two magnets together) and your hairs repel each other. If you've ever done this, you're actually taking upwards of 10,000 volts, but with such low current that it is not harmful.
On the other side of the coin, if you had low voltage and high current, you would be a dead man. You ever put a 9 volt battery to your tongue to see if it's working? If you could discharge every drop of current out of a 9 volt battery in one shot, it would kill you. I'm not exactly sure how this relates to your question, and I'm not exactly sure if I can answer your question. I've never given it much though, but I hope it helps.
Here's a question that shows off how little I know: for what things do you need high voltage, and for what things do you need high current? And, how do you control how much of each you're generating?
I've given this a bit of thought. Did you know that AAA, AA, C and D batteries all put out 1.5 volts? I have a flashlight that will run on AA, C, or D batteries. When I was in high school, I took apart a D cell flashlight, and rewired it as a battery pack for my headset tape player. The tape player normally ran on 2 AA batteries, (3 volts) which died quickly. The D batteries in the flashlight lasted much longer (6 months, if I recall) Again, back to the pipe analogy. Think of the batteries as buckets of water. The AA batteries are 1 gallon buckets, and the D batteries are 10 gallon buckets. The headset tape player was a 1 inch pipe running off of the bucket. No matter how much water is in the bucket, it won't run through the pipe any faster, but the 10 gallon buckets will take longer to become empty. As long as the tape player is getting 3 volts (1 inch water pipe) it doesn't care where the water is coming from. Make sense?
Now, that battery in your wristwatch also puts out 1.5 volts. Two of those put out 3 volts, and technically could have ran my tape player. However, they wouldn't last long. That would be like having a Dixie cup full of water, with a 1 inch pipe running off of it. The cup would be empty before the water could be of any use. This make sense to me, I hope it makes sense to you.
All right. So, I might think of devices as water wheels or turbines which need a certain square footage of water to make them turn. Do you have any control over the current? I vaguely recall that wall sockets all provide a standard current; what would happen to my devices if I hooked them up to a wall on Pluto with twice that current, or a socket on Venus with half that?
(Side question: what would happen if you gave the tape player 4.5 volts instead of three?)
I made three posts Scott, did you get all of them?
All right. So, I might think of devices as water wheels or turbines which need a certain square footage of water to make them turn. Do you have any control over the current? I vaguely recall that wall sockets all provide a standard current; what would happen to my devices if I hooked them up to a wall on Pluto with twice that current, or a socket on Venus with half that?
Yeah Scott, that's a pretty good way to look at it. As far as I know, the device won't take any more current than it needs. I was worried about that when I was planning the flashlight battery pack, would the extra current overload my tape deck? The teacher said that the voltage is what would overload it, but it won't take any more current than it needs. If you had the same voltage but twice the current, the device would run normally. If you had half the current and the same voltage, you would overload the circuit breaker.
(Side question: what would happen if you gave the tape player 4.5 volts instead of three?)
I actually wanted to see that for myself. I used an adjustable output power pack to run it one time. I kicked the voltage up to (I believe) 25 volts, and it ran fine. Then I asked the teacher about it, and he said if I had kept that up very long, I would have been buying a new tape deck. Extra current won't force its way through, extra voltage will.
Another time, I took some RC cars that ran on 6 AA batteries (9 volts). I wired that in tandem with first 6 and then 12 9 volt batteries. Still 9 volts, but a lot more available current. The car with 6 batteries ran about twice as fast, and the one with 12 batteries ran EXTREMELY fast. It was too top heavy from the weight of the batteries and wouldn't corner without flipping over, but it was still cool. In this instance, the motors on the cars were not governed to run at a set speed, and so they were saying "Gimme Gimme Gimme" when it came to the current. Hence, running faster. The tape deck was governed for a certain playing speed, and so did not draw any extra current. Most devices though would be governed to run on a certain amount of current, so that shouldn't be a problem for most things.
Of course, on an entirely different RC car, a pickup truck that I had. It ran on a 6 volt rechargeable battery pack. I wired it to a 6 volt lantern battery, expecting the same results with the previous 2 cars. Apparently, it was governed for speed, because it didn't accelerate noticeably at all. If anything, the extra weight of the battery slowed it down. So, my best guess as far as extra current and voltage is if you have extra voltage you will fry the components, but most devices won't draw anymore current than they need.
Let me fill in a few gaps.
The reason that AC works better than DC in powering a city is that you can't "transform" DC--you can tamper with the voltage but always at a cost. Using a transformer, you can run a high voltage at low current through one side and get a low voltage with high current out the other, or do the opposite.
The reason this matters is because of line losses. When you force water through the pipe, you lose a little water through the leaks, as it were. The more water you're forcing through the pipe, the more it leaks. Now, it's tricky doing water-to-electricity analogies because there are three factors and they interact. Voltage is the equivalent of the force behind the water, current of the volume of water per minute, and resistance to the diameter of the pipe. Just as with water, the more force you've got the more volume you're going to move, but the narrower the pipes the less volume you're going to move. However, things which generate electricity usually have a "maximum output", defined in watts, which is voltage times current. That is, even if I have a thousand pounds of pressure per square inch and a thousand gallons of water, if I've got a pipe a mile in diameter and a mile long I'm not going to get more than that much water through it. In the same way, my battery will produce 12 volts of pressure, and the amount of current that will create is dependent in part on the diameter of the piple--the resistance of the circuit--but in part by the limits of the battery. If I connect the two ends of the battery directly to each other in a short, I'll get the maximum current from the battery, but I won't get 12V/0R=infinite current.
I feel like I'm drifting; I hope this is still helpful.
The more current you run through the wire, the more power you lose to line losses--electricity meeting resistance in the wire and so turning to heat. Thus if you use a very high voltage and a very low current you can send large quantities of electricity longer distances, where a high current at a lower voltage will be consumed by the resistance of the wires carrying it.
On the other hand, because Voltage divided by Resistance equals Current, if you have a super high voltage and enough power available, you can have some really serious accidents from it. John mentioned the Vandergraf Generator, making your hair stand up. If you get near enough to a high voltage line, you'll get the same effect--and if you get a bit nearer, you will become the shortest path to ground, and the current will spark across the gap to hit you. John did not mention that when you touch a Vandergraf Generator, you are always supposed to be standing on a thick sheet of insulation, so that you don't become a path to ground, and you're not to let go of the generator while it is running so there's no spark between it and you. High voltage looks for shortcuts to ground, and has the power to make its own. Current will spike, even if the generator can't support the power over a long term, drawing power from other points in the system. It can be fatal.
Thus power companies run alternating current (AC) in extremely high voltages at extremely low current in very large wires over long distances, and then run them through transformers to bring them down to safe voltages for home use.
High current is needed to heat a wire, and thus to operate such things as electric heaters, toasters, incandescent light bulbs, and even vacuum tubes and cathode ray tubes (television monitors before the recent flat screen models). High voltage is better for powerful motors and electromagnets, as it allows for higher wattage (total power) at a lower current level (and thus less heat).
As to production of power, what we call batteries are usually more properly called chemical power cells. The one in your car is a battery because it is a battery of six cells combined in one case. Chemical cells produce electricity by means of an ongoing chemical reaction; the reaction is impeded by the buildup of electrical charge in the system, but connecting the ends of the battery through something enables the electrical imbalance to balance itself, and thus allows the chemical reaction to continue. Most reactions known to us produce constant output at between about 1.2 and 2.5 volts.
If you connect batteries in series, that is, with the positive of one to the negative of the next, you add the voltage. That's why your car battery is 12 volts: it is composed of six "cells" with a standard output of 2V each, connected end to end. If you connect batteries in parallel, positive to positive and negative to negative and draw the power from all the positive ends to all the negative ends, you have the same voltage but increase the potential current available. Batteries can only produce direct current; you need a device to create alternating current from them.
Using a generator, what determines the power output is the number of strands of wire passing through the magnetic field, the strength of the magnetic field, and the speed at which they move. (You can pass the magnetic field through the wires, but most systems move the wire and keep the magnet stationary.) I believe that a stronger magnetic field creates higher voltage and a faster movement creates higher current, but I can't be certain of that. Generators naturally produce alternating current, because the wires pass through the magnetic field first in one direction and then the other; there is a trick to designing a direct current generator which essentially involves changing the polarity of the connection as the generator turns, but it makes for a more complicated generator. Even so, current from a generator pulses, rising from zero to maximum and falling again. Most generators produce voltage which changes following a sine wave; a complete pass of the full sine wave (from zero positive through zero negative and back to zero) is one wave, and the number of waves per second in the frequency, which used to be given in Cycles Per Second (CPS) but in the mid twentieth century was renamed for a famous scientist, Hertz (Hz).
Photocells work more like batteries because they produce a constant chemical reaction induced by sunlight; sound and pressure generation devices work more like generators, because they are dependent on being compressed and released and so create wave forms positive and negative which match the wave form of the compression. If you compressed most of these and held them constant they would cease producing power until they were released, although some function under constant pressure to produce constant voltage (and I don't know how).
Capacitors are used in particular for what is called a stroboscopic circuit. A capacitor is in essence a large plate that holds electrons but doesn't let them go anywhere. The strobe on a camera uses a capacitor to store power equal to the voltage of the battery, but when the low-resistance bulb is dropped into the circuit it release that power at a very high current (which the battery could not match) into the bulb, causing the bulb to light brightly but using up the full power quickly so that it immediately goes out again. (Connecting the bulb to the battery would cause it to illumine more slowly and not as brightly but stay lit longer.)
An inductor is a coil of wire which uses the magnetic field created by moving electrons to induce more moving electrons. The spark system in a car uses the combination of a capacitor and in inductor. The battery stores power in the capacitor; when the points close allowing the power to go to the spark plug, it passes through the inductor which, if I've got it correctly, converts part of the power into a magnetic field and then back into electricity (I can explain how that works, but it's probably already too technical) so that the pulse lasts a bit longer. Not being an automotive engineer, I'm not at all certain why that's a good thing.
Capacitors and inductors are also used together to create tuned circuits. These are much more common in electronics, but they have the use in electricity of stabilizing electrical power at a desired frequency in alternating current. In essence, the impedance of a capacitor decreases with frequency, and the impedance of an inductor increases with frequency, and there is for any pair of capacitor and inductor a specific frequency at which the impedance of the capacitor equals that of the inductor. You can design a circuit based on that which will allow electricity of that frequency to pass and block electricity which is significantly off that frequency. Actually, someone can--I can't, although I've tuned such circuits in an old electronic keyboard once. (I should dig out that keyboard and see if I can fix it. It might be useful to me now.)
So let me hit the curve question head on:
- 9@9 eliminates the 9@10 static power used by the Daleks in the first episode of Dr. Who; you can't have usable electricity without a return path.
- 9@8 eliminates the 9@9 broadcast power used in Gamma World to power robots, and the theoretical transmission of electrical power via microwave from orbiting solar satelites to earth-based receiving stations.
- 9@7 eliminates the 9@8 use of crystal radio sets (not modern electronic ones) and Marconi sets and of solar energy power generator farms and rooftop solar-electric panels.
- 9@6 eliminates 9@7 systems which generate power from heat or which directly control resistance based on heat; this mostly affects industrial heating controls.
- 9@5 eliminates 9@6 frequency generators (capable of producing alternating current at different frequencies or of altering the frequency of alternating current), electrical filters (as described, using an inductor and a capacitor to eliminate AC outside a specific frequency, or to block either all AC or all DC current in a circult), and thermostats (simple devices designed to activate a switch at a specified temperature).
- 9@4 eliminates 9@5 transformers, capacitors, and inductors, in essence limiting power grids to a single voltage throughout and so keeping them small-scale.
- 9@3 eliminates 9@4 sound and pressure systems and electric motors.
- 9@2 eliminates 9@3 light bulbs, resistors (which have a specific constant resistance), circuit breakers (relay systems designed to open a switch when current reaches a critical level and then lock it open), and meters (coil systems which measure electrical values by the magnetic field produced).
- 9@1 eliminates 9@2 skills including generators (described above), electric heat, and fuses (wires designed to burn up when the current running through them exceeds a specific level).
--M. J. Young
As sometimes happens, while I was composing my long-winded response and doing several other things, several more posts hit the thread.
Wall sockets have a standard voltage. That standard has risen in America from 110V to 120V and there are people pushing to raise it to 125 or 130. That's because it means lower line losses in the neighborhood. People speak of "standard current" because most people don't know enough about electricity to know that it's wrong. There is also a standard frequency of 60Hz, or cycles per second. This actually matters in connection with old style televisions, and with some clocks, as the frequency controls the number of frames per second on the television and the speed of the clocks. European standards are for 220 to 250V at 50Hz; their televisions show 25 frames per second (to our 30) and so for decades shows imported from Britain had an odd look to them. More recent technology has corrected this. The amount of current available in the system is for practical purposes not limited, but since current too great for the wiring will cause it to overheat and melt and start fires, we put circuit breakers or fuses in the lines to prevent anything from exceeding the established safe parameters. Most circuits will have 20 Amp limits; 15 was the norm fifty years ago, but wiring standards have been upgraded. 240V circuits in America are created by using two 120V circuits out of phase with each other (such that one is 120 positive when the other is 120 negative), each with its own usually 20 amp breaker. Electric ovens, heaters, and water heaters can have 30 amp breakers on each side. Usually there is also a main breaker in a home that prevents the entire house from drawing more than a stated limit. Fifty years ago this was typically fifty, but most codes now require at least one hundred amp service, and many have two hundred amp service.
Current is a function of voltage over resistance; if you want to reduce the current, you increase the resistance. That's what the dimmer on your lights does.
If you put too high a voltage into a device, you will drive more current through it than it can handle, and components would overheat and burn out. Again, that's because current equals voltage over resistance, and since the resistance of the device is constant, increasing the voltage will increase the current.
John's example of the RC car that goes faster is because the higher voltage pushes more current, and thus more wattage, through the motor, which converts it to greater speed/power. On a variable speed motor, you control the speed by increasing/decreasing the voltage, which results in a change in current, which causes the motor speed to change. These are generally direct current motors, so the voltage is changed by increasing/decreasing the resistance in the circuit by putting a variable resistor in line with the motor.
--M. J. Young
John's example of the RC car that goes faster is because the higher voltage pushes more current, and thus more wattage, through the motor, which converts it to greater speed/power. On a variable speed motor, you control the speed by increasing/decreasing the voltage, which results in a change in current, which causes the motor speed to change. These are generally direct current motors, so the voltage is changed by increasing/decreasing the resistance in the circuit by putting a variable resistor in line with the motor.
You misunderstood me MJ. The voltage was still 9 volts. They were wired parallel to increase current, but keep the voltage constant. I wanted to make the batteries last longer, the added speed was kind of a side effect.
Scott, I think MJ described the pipe analogy much more accurately. I haven't studied this in about 14 years, so I'm a bit rusty on it.
To add to this ongoing electricity class:
60hz is the standard frequency for US power, but note that it's not a steady absolute. It's pretty much a daily average of what the producer puts out. There will be fluctuations as the grid reacts to increases and decreases in demand, and variations in the output of the generators. Better power companies have smoother service. A number of years ago, when troubleshooting a power issue at work, I got to see a meter which included the frequency. While I was watching, it was varying between about 57 and 62 hertz.
This mainly affects things like electrically driven mechanical clocks. They should stay reasonably accurate over time, but may vary by a minute or two at different points in the day. At college, in the radio station, we had a giant (fridge-sized) clock made of big electrical relays. At midnight when they all reset at once, the sound was impressive. Niagara-Mohawk's power was fairly dirty then, so the variations over the course of a day could be in the 5+ minute range.
One interesting thing that can be affected is a Hammond organ (or any similar instruments), which uses spinning metal tone wheels to create the sound. They are tuned to use 60hz, if the power is varying, so is the pitch of each note. This is the reason for a "line conditioner" (like a "Juice Goose" (tm)) which takes local power and converts it to a steady 110v/60hz output. Desparately vital if you want to use your Hammond on tour across Europe...
Thanks, Llarry. I'd seen that phenomenon with the clock when I was at the radio station years ago. One of my part-time DJs used to complain that the time tone sent by the ABC radio network was terribly unreliable, based on our clocks. I noted that the ABC radio network was quite accurate compared to my digital watch, and it was the clock that was hinky--but since we had two clocks, one analog and one digital, and they stayed in time with each other, I figured it had to be fluctuations in the power grid, and probably specifically in the frequency.
I am suspicious that many computer clocks are also frequency-based, as I've noticed unusual fluctuations in the time on them. This makes very little sense, given that for five bucks you can buy an electronic watch accurate to within fifteen seconds a month, but apparently makers of desktop computers don't think accurate time keeping an important function. (In fairness, I might have it wrong--it might be that keeping time is a processor function, and heavy processor loads disrupt it and compensators overcompensate. Since I don't actually know how the computer clock works, my extrapolation is based entirely on observation and comparison.) New operating systems have started including an auto-update feature which at regular intervals adjusts the time to match some online service. That's not a bad feature, except that when the U.S. Government decided to change the dates for Daylight Savings Time, all of these systems "fixed" their clocks to the wrong hour. I just disabled mine; it was too much hassle, and I can fix my own clock when I need to. My watch is usually right to within fifteen seconds anyway--a throwback to my radio days.
I'm embarrassed that I didn't know that about Hammond organs, though. I assumed that they were electronic (tuned RCL circuits), but it occurs to me that I've played on Hammonds that predate the rise of electronic musical instruments (the Farfisa may be the first real electronic organ, although I'm not certain--there were a number of church organs, such as the Conn, which may have been electronic prior to that, but the Farfisa was the first truly portable one of which I'm aware). Tone wheels are an interesting concept.
John--Your added speed benefit suggests that the standard battery was overtaxed by the load. That is, the resistance of the motor in the car was low enough that it was readily able to draw more current from the battery than the battery could deliver. Thus although the voltage was there, the power available from the battery was insufficient. (This would show as a voltage drop on the battery, in much the same way as one sees such a drop across a battery in a car when engaging the starter motor--the current demand is greater than the battery can provide, so the "force", the voltage, is reduced. That also keeps the Voltage=CurrentxResistance formula constant in the circuit.) When you added the second battery in parallel, you maintained the voltage but increased the capacity so that when you engaged the motor the paired battery was able to meet the demand. Thus you did not have the voltage drop and the motor got its full current and operated at full strength.
That should solve that mystery.
--M. J. Young
Computer clocks are usually driven off a battery on the motherboard that trickle-charges, which allows it to keep time even when the machine is off. At work, I power my machines up first thing Monday, and turn them off last thing Friday. As one of my machines aged, it started losing time. Monday morning, our network login process included an automatic update to server time (though my other machine at the time always ended up 6 minutes fast -- *nobody* ever figured that one out...). As the week went on, it would start losing time, being multiple hours behind by Friday.
Silly Hammond game: hold down a note with all the drawbars pushed in. Pull them out one at a time. Do it in the correct order, get the opening notes of the original Star Trek theme.