0
What is the Condition for terminal voltage across a secondary cell to be equal to its emf?
Wiki User
∙ 11y ago
in an open circuit, i.e. no current drawn from the cell,
producing no drop across its internal impedance
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
How can display voltage current characteristics on a cathode ray tube?
-- Connect a diode and small resistor in series across a source of AC. -- Using the point where the diode and resistor meet as a common point, connect one scope probe (H or V) to the far end of the resistor, and the other scope probe to the far end of the diode. -- One dimension of the scope display now corresponds to the voltage across the diode. -- Since the voltage across the resistor corresponds to the current through it, the other dimension of the display corresponds to the diode current. -- I leave you to work out the scale factor for the current, and the various polarities.
How are lightning bolt and a spark similar?
Both contain plasma.
If electricity was to be conducted through a stone such as granite would the process make any sounds?
If we "trickle" some charge through granite, you wouldn't hear it, and we can do that with a high enough voltage. Granite, in addition to a lot of other stone, is generally thought of as an insulating medium. Note that granite is a silicate rock, and silicates are not terribly dissimilar to glass. And we know that glass is insulative. If you have a chunk of dry granite, it won't support current flow. But if you ramp up an applied voltage while limiting current to some tiny amount, granite can be made to conduct a tiny bit. But let's look at one other instance. If we apply a large enough voltage to dry granite and do not limit current in any way, at some point the voltage will be so great that it will tear the granite apart. When we apply a voltage to a material that doesn't want to conduct, it creates a voltage stress on the material. Increasing the voltage increases the stress, and there still won't be much happening. Note that the voltage stress will be felt "through" or "across" the granite between where the electrodes are placed. And this voltage stress will appear across granite or anything else that doesn't want to conduct and to which we apply a voltage. If we continue to ramp up the voltage, at some point the voltage will be so great that it will tear electrons out of their orbitals and force them up into the conduction band. This will force the granite to conduct, and an electric arc will punch through the granite. The structure of the stone will be destroyed, and you will hear that. The arc, a stream of electrons moving along an ionized trail, will announce itself because the rock will be superheated along the path the electrons take. A shock wave will form around the arc, and this is mechanical energy which will propagate as sound. Just like with lightning.
What problems faced power stations to transmit electricity to the cities?
One major problem was how to transfer electricity over long distances, without loosing the current. The current may dissipate over a long circuit, so what you get at the city is only a fraction of what you generated at the plant. This problem was overcome by using large transformers. They convert high current/low voltage to a low current but very high voltage. The electricity is then carried across land with minimal losses and once nearer its destination will be converted back to a higher current/lower voltage through the use of further transformers.
What is the condition of the atmosphere at a certain time and place called?
It is called the weather. All weather takes place in the atmosphere though it affects the ground.
What is the difference between the terminal voltage and the source voltage?
the source voltage is the voltage that measured exactly after the voltage source , but the terminal voltage is the voltage that measured in the load terminals , which equal to the source voltage minus the drop voltage on the transmission line .
What happens when secondary of the transformer is open?
The secondary winding leakage inductance limits the current during a short. It seems that the current through the primary is limited by winding resistance and leakage resistance when the secondary is shorted.
What happend if secondry is kept open in Current transformer?
A CT attempts to push a specific ratio of primary current through the secondary. If the secondary burden is a very high resistance (as in an open circuit), the voltage developped across the secondary will build up until it reaches the theoretical limit of the primary voltage. Before it gets to this voltage, it will arc across the air gap in the secondary open (often between two terminal blocks). As an old tech once told me, you only open the secondary of a CT once...the arcs can be fairly spectacular.
What voltage is being applied across the secondary circuit?
A voltage is never applied to the secondary It can be used as a source but hen it becomes the primary by definition
If the voltage in a transformer is twelve volts and the primary coil has ten turns and the secondary coil has twenty what is the voltage across the secondary coil?
I assume the primary has 12 volts applied. The voltage ratio from primary / secondary is equivalent to the turns ratio = 10/20, so the primary voltage is 1/2 of the secondary voltage. The secondary voltage is 24.
What is the condition that prevent the current to pass across diode?
if the voltage across the diode is less than the cut-in voltage of that particular diode .
How do you comfirm thyristor condition?
A thyristor if conducting will have a very small voltage drop across if not then the rail voltage will be evident across the device
What is voltage regulation?
Voltage regulation:(from point of view of electrical machines or generator): It is the change in voltage in between the full loaded and no loaded condition. When there are no loads connected the terminal voltage is equal to the generated voltage in the generator. But when load is connected the terminal voltage is found to be lass than the no loaded condition, due to armature resistance leakage reactance.This phenomena is expressed as, % reg=(Vnl-Vfl)/Vfl * 100%.Which is Voltage regulation. ************************************************************ An ideal voltage source has zero internal impedance. A practical one, even a good one, has internal impedance. With no load on the source, the terminal voltage will have a given value. Once a load current is drawn there will be a voltage drop across the source's internal impedance, and the terminal voltage will therefore drop. The higher the load current, the higher the voltage drop. A regulator circuit, added after the source, can counter the effect of the source's impedance and maintain an output voltage which is more constant than the source itself can achieve.
What type of voltage is passed trough a transformer?
Voltage doesn't 'pass through' anything! Voltage is another word for 'potential difference', and is measured between two points in a circuit. For a transformer to work, it's necessary to apply an a.c. voltage across the transformer's primary terminals.
How resistor can be distinguished?
Resistor is a two terminal electronic component that produces voltage across its terminal. It is usually rounded by 5 colors. Simple illustration below. The "I" represent colors. . . terminal ======[ I I I I I]====== terminal
Why the secondary of the current transformer should not be open circuited?
The secondary of a CT must always have a load connected. An open circuit secondary can result in the development of a dangerously high secondary voltage. If a CT is energized but is not used, the output terminals of the CT must be shorted out.
How do you charge a capacitor?
You charge a capacitor by placing DC voltage across its terminal leads. Make sure when using a polarized capacitor to place positive voltage across the positive lead (the longer lead) and negative voltage across the negative lead. Also make sure that the voltage you charge the capacitor to doesn't exceeds its voltage rating.
