# Is there any change in the current or voltage coming from the other end of the dielectric after the dielectric breakdown occurs?

Yes. Once dielectric breakdown occurs the circuit is now completed through a conductive breakdown channel in the dielectric. The current injected in one end of the dielectric is matched by the current coming out of the other end.

### What is the influence of gate voltage on drain source breakdown voltage in mos transistors?

Drain-to-source breakdown voltage (BVdss) should not change appreciably until the gate-to-source voltage (Vgs) approaches the device's threshold voltage (Vth). In that case, the drain to source voltage becomes the product of the drain-to-source current (Ids) and the device's on-state resistance (Rds-on) at the given Vgs.

### When current through a zener diode increases by a factor of 2 by what factor does the voltage across the zener diode increase?

If the zener diode is in zener breakdown the voltage across the zener diode remains constant regardless of current (for the ideal zener diode). Real zener diodes have parasitic resistance that causes the voltage across the zener diode to increase slightly with increased current, but due to temperature dependant variations in this parasitic resistance as well as temperature dependant variations in the zener breakdown voltage, this change in voltage in real zener diodes cannot be…

### How you reduce capacitor size while keeping the capacitance?

You can reduce the size of the plates (thus making the capacitor smaller physically) if you also do one or both of the following: move the plates closer together (which also reduces size, but lowers the breakdown voltage) use a dielectric with a higher dielectric constant Of course these changes must be made at the time of manufacture, they cannot be done to change an existing capacitor.

### How does capacitor charges by opposing the change in voltage?

Capacitors charge by transferring charge from one plate to the other. This is not the same as a battery, though it can seem so. They oppose a change in voltage because the two plates are close to each other, separated by the dielectric, and the transfer of charge requires current. Once charged, however, the current becomes zero. The differential equation describing a capacitor is dv/dt = i/c, or volts per second = current over capacitance.

### How could a capacitor have voltage but no current?

Voltage and current are two different things. Voltage is potential energy per charge, in joules per coulomb, while current is charge transfer rate, in coulombs per second. Its that same as saying that a battery has voltage but no current, because there is no load. Well, a capacitor resists a change in voltage by requiring a current to change the voltage. Once that voltage is achieved, there is infinite resistance to the voltage, and thus…

### What is the dependence of reverse saturation current in a P-N diode on applied voltage and temperature?

In a PN junction diode, the reverse current is due to the diﬀusive ﬂow of minority electrons from the p-side to the n-side and the minority holes from the n-side to the p-side. Hence IS, reverse saturation current depends on the diﬀusion coeﬃcient of electrons and holes. The minority carriers are thermally generated so the reverse saturation current is almost unaﬀected by the reverse bias but is highly sensitive to temperature changes. so , as…

### How is current and voltage related to the power supplied by the source in parallel?

In parallel circuit there is no change of ratting voltage but there is also change of current because in parallel circuit in every node of the apply circuit there is no change of voltage but the current distributed through the node as per as required and it reduces the current reading of the main current source.

### What is the phase relationship of voltage across a capacitor and current though the capacitor?

In a capacitor, the current LEADS the voltage by 90 degrees, or to put it the other way, the voltage LAGS the current by 90 degrees. This is because the current in a capacitor depends on the RATE OF CHANGE in voltage across it, and the greatest rate of change is when the voltage is passing through zero (the sine-wave is at its steepest). So current will peak when the voltage is zero, and will…

### Why does the voltage lead the current in inductor?

Difficult to explain without a diagram. However, the voltage induced into a conductor is maximum when the rate of change of current is greatest. This voltage opposes the change in current, so acts in the opposite sense to the current. Since the supply voltage is equal and opposite the induced voltage, it acts in the positive sense when the current is increasing and passing through zero -therefore, the supply voltage 'peaks' 90 degrees ahead of…

### What will happen to the electric field of capacitor if temp of polarized dielectric is increased?

That will depend on the dielectric. There will be two main effects - any change in the permeativity of the dielectric, and thermal expansion which will increase the distance between the plates. There will also be an change (probably an increase), in leakage current through the dielectric. Any change is very likely to be small or insignificant - I have worked in a factory making capacitors and temperatures were very variable, not controlled, for measurements…

### How can current lag or lead voltage in an AC circuit isn't current a function of voltage etc?

Current can lag or lead voltage in an AC circuit when the load is what we call reactive. The idea that current is purely a function of voltage only applies when working with DC, or when working with purely resistive loads, such as light bulbs and toasters. Not so, when dealing with motors and power supplies. What happens is that an inductor resists a change in current. That means that, given a particular voltage and…

### What is the phase angle between voltage and current in a purely capacitive circuit?

Current leads voltage (or voltage lags current) by 90Â° in a purely capacitive circuit. Try to remember it this way: capacitors resist change in voltage, hence the voltage lags (they resist voltage change because the voltage first goes to charging up the electric field in the capacitor). Inductors resist change in current (energy in an inductor is in the form of magnetic fields, which are caused by the current through the wire). Remember an inductor…

### How do you calculate induced voltage in a coil?

The voltage induced into a coil is proportional to the rate of change of current (dI/dt) through that coil. If the current is a constant value, then no voltage is induced. The equation is as follows: V = - L (dI/dt)where L is the inductance of the coil, measured in henrys, and dI/dt means 'change of current divided by change of time'. The minus sign indicates that the induced voltage opposes the change in current.

### What determines whether an induced current is a direct current or an alternating current?

There is no such thing as an 'induced current'. What is 'induced' is a voltage. The direction of the induced voltage is determined by the direction of the changing current that induces that voltage, because the induced voltage will always act to oppose that change in current. So, if the current is increasing, then the direction of the induced voltage will act to oppose the increase in current. If the current is decreasing, then the…

### What makes electric currents smaller or larger?

Electric current as we usually describe it is the flow of electrons. Current is caused to flow by voltage, which can be looked at as "electrical pressure" that forces electrons to move. Currents can be made smaller or larger by decreasing the voltage across a fixed amount of resistance. As resistance is the quality of "resisting" or "limiting" current flow, we can change resistance to change current. For a give voltage, if we increase the…

### Why zener diode can be used as a voltage regulater?

The zener diode can be used as a voltage regulator because its reverse bias (technically, reverse breakdown) current to voltage curve is particularly steep, resulting in very little voltage change even when current changes. Any diode, actually, exhibits this steep curve in the forward direction, but it is steeper in the reverse direction in zeners, making them more suitable for this application. This works because of the doping that is used in the PN junction…

### Why current lead voltage in coil?

because a coil is an inductor,for current leads voltage in an inductor Answer It doesn't! Current lags voltage in a coil. In a purely-inductive circuit, the current lags the supply voltage by 90 degrees. The reason for this is 'self inductance'. Whenever a current changes, a voltage is induced into the coil which opposes that change in current. The maximum self-induced voltage occurs when the rate of change in current is greatest. The greatest positive…

### How does a zener diode work?

A zener diode is designed to be operated in reverse bias, and have a specified breakdown voltage. For example, if you wanted a part that is supposed to get 10V applied to it, and you only have a 12V rail, you can put a resistor and a 10V zener diode in series, and the zener diode will make sure that only 10V get dropped across it. Any more and it will begin conducting. It will…

### Why not change the frequency in transformer?

Because you can't. The secondary voltage is caused by the change in current (di/dt) in the primary. Likewise, when current flows in the secondary, there is a "back electromagnetic force" that induces a voltage in primary that causes current to increase in the primary. This transformer action is determined by the change in current, and doesn't by nature change the frequency.

### Do you add electrical supply voltage and induced voltage of a coil to get total voltage on the coil?

The induced voltage acts to oppose any change in current that is causing it. So, if the current is increasing, then the induced voltage will act in the opposite direction to the supply voltage; if the current is decreasing, then the induced voltage will act in the same direction as the supply voltage.

### When are voltage and current out of phase?

Voltage and current are out of phase when the load is reactive, as opposed to purely resistive. This is caused by capacitance (capacitive reactance) and/or inductance (inductive reactance). Basically, capacitive reactance resists a change in voltage, and inductive reactance resists a change in current. This results in a phase shift of current relative to voltage, plus or leading for capacitive, minus or lagging for inductance.

### Why in inductor the current lags the voltage?

The voltage induced into a coil opposes the supply voltage and is proportional to the rate of change of current. The greatest (positive) rate of change of current occurs when the current waveform is at its steepest -i.e. as it passes through the zeros axis. At this point, the induced voltage is at its maximum value and is equal but opposite to the supply voltage. So the current must then reach its peak 90 electrical…