Why capacitor blocks direct current?
481957
Capacitors are built with a gap between the two conductors, or sides of the component.  So it is not completely accurate to say that they block direct current, because enough direct current applied to one side will jump the gap (think of a spark plug).\n\nHowever, applied in a circuit correctly, that is why it is said they block dc current.  Make sense?
930867
Capacitors = stored energy, leaking dieletric (if hazardous), and/or reverse polarity may cause rupture/failure. Over-voltage can cause failure also. Always store de-energized and shorted.\n\nInductors = No hazard if de-energized. Inductors in service with an over-current condition can overheat and cause burns or failure of the component.
580159
The AC Switch Block allows a conventional 5V signal to control a much larger AC line. The switch can handle up to 16 Amps of current provided it is kept cool enough. At 110V, this is more than 1500W. We suggest that this limit be approached very carefully and recommend staying far beneath this.\n\nOnce an AC line is connected to the AC terminals, several places on the board will become live. This makes it absolutely essential that the board be mounted in a way that will prevent short circuits and accidental human contact. This is true even for rough prototypes or trial hook ups. Treat AC line voltages with much respect.\n\nHow Do I Use This?\nWith your AC device unplugged, first determine which cable from your AC device's power cord should be switched. It's best to switch the "live" or "hot" wire. On any AC outlet, there are usually 3 slots (sometimes 2). The right slot, which is slightly smaller than the left slot, is the "live" slot - check which prong plugs into this slot when you plug the AC device in to confirm which wire is live.\n\nOnce you've determined which wire is live, snip it in two somewhere along its length, strip about 1/8" insulation away from both the open ends, and tin the exposed wires. Make sure to leave enough slack on the cord for the two tinned ends to be inserted to the two AC connectors on the AC Switch Block.\n\nA small 5V signal applied to the D0 input will control the switch that turns the AC device on and off. Run a wire from the 0V connector on the AC Switch to the ground of the device providing the 5V signal. Double check that all your connections are correct, and plug in the AC device to the wall - now, a 5V signal on the D0 input turns the device on and a 0V signal turns it off.\n\nApplications\n-Automate Your Household. Many household appliances such as lights, fans, blenders, drills, vacuums, etc. run on AC power. Now you can use the behavior from a Poly Block an Intro Module, or any other device that put out 5V, to control these kinds of devices.
374690
DC is Direct Current in which the electrons move in one direction through the wire all the time.\nAC is Alternating Current in which the electrons flow one way for a short time and then switch directions and flow the other way for a while.\nThe constant direction switching does not interfere with the work the electricity does if the devices using it are properly designed. Some devices, like incandescent light bulbs, work equally well with either type of current. Other types of devices, like transformers, depend on the constant switching to operate.
723475
The reason polarity matters in an electrolytic capacitor is because the dielectric(the insulator between the two conducting plates) was manufactured by passing a direct current to a metal plate immersed in an electrolytic solution.   If you feed a current in the opposite direction through the capacitor, you'll destroy the dielectric.   If it's a large current the capacitor will explode.   Other types of capacitor can handle current in either direction.
189253
current is the flow of electrons batteries and capacitor store the potential for current so in a way you can store it
282019
yes, using a static capacitor
143587
Here is something that may or may not help\n\nIf you take a largish non polarized capacitor\n≥45µF\nand you apply AC 120V 60Hz to one side of it\nwith no ground reference! \nyou can then place \na small wattage low voltage lamp across the \ncapacitor terminals and it will light.\n\nThis is a way to send power over a single conductor.\nI have done this.\nI think it would also work with a coil instead of a cap.\n\nAs far as I can tell\nTesla wanted to use this principle to \npower the Earth\nusing the earth as the single conductor.\n\ndo you mean generate electric power at the other site?\ndo you mean energize an electric generator?\nmaybe for a very focussed wave and relatively small distance or a tiny amount of power.\nBut that is sort of why we use wires so much!\n\ndon't RFID cards transduce a wave and send it back\nI mean technically that is an example right?
470470
I'd like to know exactly what you're trying to do. Using the wrong type of capacitor or one with the wrong values could explode and burn. I'm talking about a pretty violent explosion at 110 VAC!  A Snubber will not work because that is now what they are for. A snubber is used on the gate of SCRs to prevent false retriggering especially on high power circuits. What you need is a Thermistor. This is a flat round device with two wires coming out of the edge. The thermistor will be put in series between the power switch and the capacitor. At normal room temperatures the thermistor might have about 50 Ohms of resistance. When it warms up, (almost instantly), the resistance drops to about zero. This action limits and controls the initial power surge into the capacitor when the switch is thrown thereby preventing damage to the switch. You need to know the voltage and current load to select the right thermistor otherwise it becomes smoke.\n\nPlese use caution: Capacitors can store huge amounts of power and will COMPLETELY DISCHARGE IMMEDIATELY.\n\nA large capacitor, when shorted out, can blow a 1/4 inch screwdriver in half! Sounds cool but the missing part is burning molten metal flying at you! Please be Careful!
694027
(rek´ti-fī´´&r) (n.) A component of a circuit that allows current to pass in one direction yet blocks the flow of current in the other direction. Rectifiers are used to convert AC into DC
107875
Limit the load current.\nEDIT: This is often done by adjusting the stator field current if it's a generator with an electromagnet (not permanent magnet) field.
371756
Assuming that you are not removing the SCR from the circuit.\nTry to look at the gate signal and the output at the cathode on a double beam 'scope while the servo is trying to operate. Or disconnect the gate and try to turn the SCR on from an external source and see if you get output motion from the servo or whatever the output is.Some caution required with 440 v !!Some recollection from 25 yrs ago may help ? Making a bridge  or H-switch to drive a 1/2 hp dc motor. Collected a pile of dud transistors on bench until able to prevent simultaneous turn-on down one side of the bridge. This is prevented by correct commutation and ensuring that during switching, the instantaneous power dissipation in the device remains outside the specified region.Commutation is aided by placing an air-core inductor in series with the load and then usng a secondary winding on this to make sure that when one side is conducting that the other arms are turned off.It is somewhat tricky and very critical.
969269
Whether or not a motor needs a capacitor depends on the type of motor. There are at least 5 or 6 different types of single phase motor, some requiring capacitors, some not (pf correction aside).\n\nIt is likely that the device wired to the motor in the dishwasher is required where ever you use it. It is also usual for start capacitors to be mounted on the side of the motor but may not always be the case. A capacitor is normally cylindrical and will have a value in micro farad.\n\nTake a look at the link below and see if any of the options on it resemble what you have.\nhttp://www.tcf.com/TCFBlower/pdfs/engr_data/ED1100.pdf\n\nThey don't mention another type that is often used in domestic appliances but is clear to identify by the fact it has brushes and commutator, this type would not normally need any separate control\n\nI have even found a dc motor in a standard washing machine, obviously a dc motor requires some other circuitry to use on the mains. I don't know how common this would be to find since I don't take apart too many domestic appliances.
365027
The capacity of a capacitor is measured in farads (F). Ususally they range from several picofarads (pF) to several microfarads (µF). For the measurement, look on the capacitor itself or if it is a disk capacitor then there is a system for figuring that out (look it up).
937573
Capacitors serve a couple of purposes beyond what you mention.  They allow the ac component of a dc signal to pass, such as in a power supply, thereby smoothing the dc output.  These are polarity-sensitive caps called electrolytics.  The smaller, non-polarized caps are used as coupling devices for RF devices.  There are, in fact, several uses for the device, and building functioning circuits without them would be almost impossible.
644077
The voltage at which the attractive forces between the capacitor plates overpowers the fasteners.\n\nTake a look\n\nwww.math.ubc.ca/~ward/papers_ps/memspap.pdf
849597
Both inductors and capacitors store energy, in the form of magnetic or electric fields, respectively, so they have some possibility of discharging that energy in a dangerous way. Shorting out a large capacitor, for example, would produce a large current. Overheating an inductor (too much current) might cause the coil to fail, and then the magnetic field decay would produce a voltage spike I think. I would assume the risks with small components are quite small.