What does milliamp-hours mean?
A milliamp-hour is one thousanth of an amp-hour. For example: if you have a fully charged battery of 500 mAh (milliamp-hours), it is able to feed a lamp which draws a current of 500 mA for one hour. It also is able to feed a mobile phone in standby over a period of 50 hours, if it draws a current of 10 mA.
Alternative AnswerA milliampere hour (not 'milliamp hour'!) is one-thousandth of an ampere hour, which is a unit of electrical charge. The SI unit for charge is a coulomb, which is a special name given to an ampere second. So, and ampere hour is 60 x 60, or 360 times larger than a coulomb.
How do you convert 12 volts to 4 volts?
Using a voltage regulator (LM78XX come to mind), or through Pulse Width Modulation.
In the first case, the typical output power will be at 4W tops (LM78XX are typically rated at around 1A of current). In the second case it's up to the design of the PWM circuit, I guess.
A simple PWM circuit would include an oscillator (or a square signal generator, doesn't matter) driving a transistor in a predictable pattern (turning it on for 1/3rd of the time), the aforementioned transistor, and a capacitor to smooth the ripples out. If for 1 out of 3 seconds it's 12V, and for the remaining 2 seconds it's 0V, then (12+0+0)/3 = 4V. The current rating would depend on the load and the transistor's ability. For higher loads it may be advisable to drive a second-stage, high current transistor. Also, saturation concerns come to mind, but that's a different story.
There is a third option, but it's overkill in this situation -- using a transistor and a capacitor to form a resonant circuit driving a transformer. However, this type of design is typically found in applications where the voltage needs to be stepped up, not down (ie. LCD/keyboard backlights, cold-cathode lights and the like).
The bulb that glows brighter has a smaller resistance. This is because a larger current flows through the bulb with smaller resistance, resulting in it glowing brighter.
GFCI=Ground Fault Circuit Interrupter
It's an electronic circuit breaker that compares the current on two wires. If the current is NOT equal, the breaker trips and does so quickly enough to prevent electrocution in the event of a "ground fault".
Can you change the wall outlet to fit a 4 prong dryer outlet?
It's probably more difficult than you might expect.
I'm assuming you have a NEMA 5-15R outlet, and you want to plug in a dryer that has a NEMA 14-30P plug at the end of its electric cable.
The NEMA 5-15R outlet is by far the most common type of outlet in North America.
It has two flat slots (hot and neutral), and a round safety ground hole.
It is rated for 15 A and 125 V.
On the other hand, most electric clothes dryers have an electric cable with a NEMA 14-30P plug on the end.
It has two flat slots (2 hots from 2 different phases, each one 120 V from neutral, and each one rated at 30 A), an L slot (neutral), and a round safety plug.
It is possible for an electrician to "fish" a electric cable carrying the necessary phases through the wall from the fuse box to that outlet, and then pull the old outlet and install a new outlet.
If one merely did that last part -- pulled the old outlet and placed a new outlet -- without the proper electrical cables in the wall behind it, then the dryer would probably blow the fuse at the fusebox every time it was turned on.
What arrangement of three cells would result in the longest life?
A combination of regular exercise, balanced nutrition, and adequate sleep is key for maintaining a long and healthy life. Regular physical activity helps keep the body strong, balanced nutrition provides essential nutrients for overall health, and quality sleep is crucial for rest and recovery. Combining these three factors can help promote longevity and well-being.
What arrangement of three cells would result in the greatest electric current?
I haven't studied this for awhile, but... I assume by cell, you mean a voltage supply, like a battery. It depends on what else is in the circuit. If your circuit has a typical amount of resistance, then connecting the cells in series (as opposed to in parallel) will result in the largest voltage. Higher voltage means greater current across a resistor. However, if the resistance of the circuit is very low (like in a short circuit), then your batteries' own internal resistance may be the most significant factor, and batteries arranged in parallel may be able to sustain a higher current.
If phase and neutral get reversed in a power line, electrical appliances may malfunction, and there is a risk of electrical shock to users. To rectify this issue, you must immediately shut off the power supply and contact a qualified electrician to correct the wiring configuration. Reversing phase and neutral can be dangerous and should be addressed promptly to prevent any potential hazards.
Ways to solve unbalanced wye connection?
To balance a wye system you have to find the wattage connected to each breaker on each of the three phase legs. Total the wattages of the three individual phases legs. The difference in wattage is the unbalanced load. Then is is just a matter of deciding which breaker load should be moved to another leg to try and make all three legs as equal as possible. Working with an off and on again load wattage is sometimes hard to do because at certain times some of the loads will not be on. You should be able to get close but never right on. The only time you will ever get a completely balanced load is if the load is three phase resistance heating.
An electrician would use the AC voltage setting on a voltmeter to measure the voltage in a standard household electrical socket. This setting is specifically designed to measure the alternating current voltage commonly found in household electrical systems.
What is the power factor of a DC system?
It would be unity, or 1.0. Since the voltage in a DC circuit does not vary with time, there can be no phase displacement of the current waveform, and therefore the current could not lead or lag the voltage waveform.
What can 240 volts of electricity do to a person with wet hands?
240 volts of electricity can cause electric shock, which can lead to muscle spasms, burns, organ damage, and potentially death. The combination of wet hands and electricity increases the conductivity, making it easier for the current to flow through the body. It is important to always keep electrical appliances and outlets away from water and to never handle them with wet hands.
What kind of material does a magnet stick to?
A magnet sticks to materials that are ferromagnetic, such as iron, nickel, and cobalt. Other materials like steel and alloys containing these metals will also be attracted to a magnet.
If your breaker box is balanced will your electric bill be less?
No. In North America you are billed on the consumption of watts (amps x volts). Both legs L1 and L2 are monitored inside the watt-meter that is situated on the side of your house and are independent from the unbalanced or balanced load on the neutral.
How do you determine best gauge of wire to use?
There is a formula based on wire type, length, and current. The easiest way nowadays is to use an online calculator. Remember when using that calculator that both wires in the circuit count (hot & neutral), so don't divide the length by 2. Just enter the length of your run.
On a 208 120 volt 3 phase electrical system what is the color code for the wires?
208/120 is typical for the US, so these are the colors for the US: A phase: black -------------------In Canada; A phase - Red B phase: red-------------------------------------B phase - Black C phase: blue -----------------------------------C phase - Blue neutral: white -----------------------------------neutral: white ground: green or green with yellow stripe
Can I use a 220V oven with 110V outlet?
No, and if you don't have a 220v outlet, you will need an electrician to run a #8 copper wire with a direct line to the electrical panel (40 or 50 amp), depending on the oven's requirments - check the manual.
What is the height to place a light switch in New Zealand?
The correct answer to your question will depend on the exact location of the light switches in particular if the location is subject to damp conditions, such as in a bathroom, shower room, kitchen or anywhere outside a building.
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What is the mains voltage in your home?
The mains voltage in a typical home in the United States is 120 volts. In other parts of the world, such as Europe, the mains voltage is usually around 230 volts. It's important to note that voltage can vary depending on location and electrical systems in use.
Can you wire two 240 volt room air conditioners on one breaker?
This will depend upon the current draw of the ACs as well as the size of the circuit. My guess, based upon what 240V units tend to draw, is that you probably won't be able to, especially if the circuit is only 15 Amps. With a 20 Amp, you MIGHT be able to. You will have to check the nameplates on each unit to find what the current draw is and ADD THEM TOGETHER. And remember that AC units should be considered a continuous load. This is when a load may run for three hours or longer. Here, you must "derate " the circuit by 80%. So a 15 Amp circuit should only have a load of 12 Amps; while a 20 Amp should have a load of only 16 Amps. My best "guesstimate" is that they will need their own circuit.
Can you change a 2prong to a 3 prong on a window air conditioner?
It is not recommended to convert a two-prong plug to a three-prong plug on a window air conditioner as it may compromise safety. The third prong provides a grounding connection which is important for protecting against electrical shocks. It's best to use a three-prong outlet or consult an electrician for proper installation.
Most outdoor outlets are on a GFCI device. Depending on when your house was wired the outside plugs may be fed from the GFCI in the bathroom. The method used was to take the downstream side of the bathroom GFCI and run it to the outside plugs all around the house. If you want to delve into this further open a discuss question page
Holophane ballast re400mh48hrw how do i wire them and are they 120 or 220?
On your model number the figures after 400MH are the voltages for that ballast. A 40 represents 240 volts, 12 represents 120 volts and yours 48 represents 480 volts. Looks like this is a industrial fixture and not meant for residential use.
What is Ir value of a circuit breaker?
Ir is the Interrupt rating of the circuit breaker. It is the maximum amount of current the breaker can withstand without damage. In a molded case breaker's electronic trip mechanism, Ir is the continuous current rating that you select, to trip the breaker at a given overload current. Standard requirements request that the breaker trips at 2 hours with an overload of 135% and will trip as a function of I squared x time selected for higher currents.
What is an electrical ballast?
Firstly, there are a few meanings for the word ballast, and they are used in different contexts.
In an electrical context:
Electrically, It adds resistance to limit the current. In a fluorescent light fitting, the ballast adds resistance. Once the lamp conducts, it presents a very low resistance to the circuit and would draw too much current. The ballast coil also has reactance and provides a back emf pulse, to enable the lamp to fire (conduct) when it is interrupted by the starter.
In an a shipping context:
Ballast is used in ships and submarines (both new and old) to provide stability to the vessel within the water. Normally the trim of a boat in the water will differ whether it carrying a cargo or not, if the ship is lighter and higher in the water it is more inclined to roll from side to side in heavy weather. In order to prevent this ballast tanks are used in ships, these are then filled with seawater in to make the ship heavier (lower) in the water and less prone to tilting. Before the ship takes on cargo the tanks are pumped out making the boat "ride" higher in the water. Earlier wooden vessels also used ballast, but would use stones, rock or bricks for this purpose.
In submarines, ballast tanks are flooded with water or purged using compressed air in order to maintain neutral buoyancy, or to allow the submarine to ascend or descend.
In hydraulics/ irrigation terms:
Ballast tanks (sometimes called buffer tanks) are used in irrigation and plumbing systems to provide a buffer between supply and demand systems. A simple example of this is the water tank of your toilet. The system, when flushing requires a fairly substantial amount of water, the mains water supply of a typical house does not have this volume all at once, so the water is stored in a small ballast tank. When you press the flusher a larger volume of water that can normally be supplied by the house water supply is release - giving you a clean bowl.