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The relay coil is an inductor and, as such, resists a change in current. When you de-energize the coil, it attempts to maintain the current flow, but it cannot because you have opened the circuit. This causes a high voltage spike to be developed across the coil which is of opposite polarity to the normal current. The diode conducts, dissipating the current and preventing the voltage from exceeding the safe operating voltage of the driving circuit, often a transistor.
The Diode is wired so that it is in reverse during normal operation, so no current passes through the diode and does not affect the coil it is parallel connected to.
What else can I help you with?
What is a sweep generator?
A sweep generator is an instrument used to align IF circuits in older FM radios that used adjustable IF coils in the circuits. The generator "sweeps" the frequencies on either side of a set center frequency. When this signal is applied to the front end of an IF circuit, the responce from the IF circuit can be observed at the end of the IF with an oscilloscope allowing the IF coils in the circuit to be adjusted to the desired bandwidth and responce of the circuit.
Can back EMF be greater than battery EMF?
Yes. Let's look at an example. A 12 volt system can operate a 12 volt relay coil to actuate the plunger. But when the field of the coil collapses in the instant following when the coil is de-energized, the collapsing field can generate an "inductive kick" that can easily reach several hundred volts. Relay coils frequently have diodes across their coils to shunt this voltage through the coil and prevent it reaching other parts of the circuit because it is a higher voltage and could damage components. As a closing note, you're not "getting something for nothing" or generating more energy out of the coil than originally went in. The power in still equals the power out (less any loss). With a properly designed coil utilizing Marko Rodin's configuration, losses are negligible.
What is field coils?
field coils generally refer to the electromagnetic coils on the stator ( the stationary part of an electric motor ). these generate the magnetic field(s) necessary to put the rotor ( the rotating part of the motor ) into motion.
What song do they play in the Sorcerer's Apprentice with the Tesla coils?
Secrets by OneRepublic
Why to use centre tapped transformer in bridge wave rectifier?
In a rectifier, a center-tapped transformer and two diodes can form a full-wave rectifier that allows both half-cycles of the AC waveform to contribute to the direct current, making it smoother than a half-wave rectifier. This form of circuit saves on rectifier diodes compared to a diode bridge, but has poorer utilization of the transformer windings.
What is DC reactor in inverter?
This is used to improve the input power factor of the inverter power supply and reduce harmonics. The ''DC reactor'' is more effective than the input reactor in improving the power factorDC reactors (link chokes) are connected after the input diodes in the power circuit. One of the disadvantage of the DC reactors is they are located after the input diodes, and do not protect the diodes from possible voltage transients. One coil is needed in a DC circuit versus 3 coils in the AC circuit. Additionally DC reactors smoothing the current flow limits the high peak current pulses from abusing the capacitor bank inside the converter.
How many coils in air circuit breaker?
Air circuit breakers typically have multiple coils for different functions, such as opening and closing the circuit breaker, tripping mechanisms, and for auxiliary purposes. The exact number of coils can vary depending on the manufacturer and specific model of the air circuit breaker.
What is the different between 3phase plus N generator coil and motor coil?
Generator coils generate the voltage, motor coils use the generated voltage.
What are the construction details of a brushless alternator?
A brushless alternator assembly will have the following major components. These include the case, stator, diodes, bearings, shaft, regulator and coils.
Why do power plants use generators with many coils of wire?
Power plants use generators with many coils of wire to increase the strength of the magnetic field generated, thus increasing the voltage produced. More coils also allow for a greater amount of electricity to be generated efficiently. These generators are designed to handle high currents and produce electricity more consistently for a wider area.
What is a sweep generator?
A sweep generator is an instrument used to align IF circuits in older FM radios that used adjustable IF coils in the circuits. The generator "sweeps" the frequencies on either side of a set center frequency. When this signal is applied to the front end of an IF circuit, the responce from the IF circuit can be observed at the end of the IF with an oscilloscope allowing the IF coils in the circuit to be adjusted to the desired bandwidth and responce of the circuit.
Why wire in the coils of electromagnets must be isolated?
Presumably you mean 'insulated', rather than 'isolated'? In which case it is rather obvious, isn't it? If the coils weren't insulated, then the individual windings would short-circuit, and the coil itself would short circuit with the core of the electromagnet.
Is electricity generated by rotating magnets around copper coils AC or DC?
It is AC, alternating current. To create DC the generated power needs to go through a full wave rectifier.
What effect does decreasing the number of coils around the nail have on the strength of the electromagnet?
Decreasing the number of coils around the nail decreases the strength of the electromagnet. This is because fewer coils result in fewer magnetic field lines being produced, which weakens the magnetic force generated by the electromagnet.
How does the number of coils relate to the magnets strength?
The number of coils in a coil of wire does not directly affect the strength of a magnet. The strength of a magnet is determined by factors such as the material it is made of, its size, and its composition, rather than the number of coils in a nearby wire. However, the number of coils in a wire can affect the magnetic field generated when a current flows through it.
How does the number of coils affect the magnetic force?
The number of coils in a coil of wire affects the magnetic force by increasing the strength of the magnetic field generated. More coils result in a stronger magnetic field due to increased current flow and the formation of more magnetic field lines. This increase in magnetic force is proportional to the number of coils in the wire.
What happen if you apply triangular input to transformer?
there will be no neutral point in the circuit and high voltage will be across the transformer coils
