# Voltage power and current relationship interview

### Basic electrical quantities: current, voltage, power (article) | Khan Academy

Build an intuitive understanding of current and voltage, and power. in a fixed amount of time, it can be expressed mathematically using the following equation. phase relationship between current and voltage in a series resonant circuit? a source with known characteristics so that there is maximum power transfer?. Normally when the voltage increases the current increases with (ohm law). Is that the power delivered by the engine which is 37 kw is.

Reverse Power flow relay are used in generating station's protection. A generating stations is supposed to fed power to the grid and in case generating units are off,there is no generation in the plant then plant may take power from grid. To stop the flow of power from grid to generator we use reverse power relay. It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load. Definition Of Power Electronics?

Power electronics refers to control and conversion of electrical power by power semiconductor devices wherein these devices operate as switches. The main task of power electronics is to control and convert electrical power from one form to another.

## Current and voltage relationship in an electric motor

AC to DC conversion: Rectifier is used for converting an AC voltage to a DC voltage. Variable speed dc drives, Battery chargers, DC power supplies and Power supply for a specific application like electroplating. DC to AC conversion: Inverter circuit is used to convert DC voltage to an alternating voltage. Emergency lighting systems, AC variable speed drives, Un-interrupted power supplies and Frequency converters.

### Resistance Is Current Over Voltage

DC to DC conversion: A dc-to-dc converter circuit was called a chopper. DC drive, Battery charger and DC power supply. AC to AC conversion: A cycloconverter converts an AC voltage to another AC voltage. It is rarely used.

Can be used for controlling the speed of an AC traction motor Question SCR or thyristor will have three regions of operations based on the mode in which the device is connected in the circuit. When the cathode of the thyristor is made positive with respect to the anode and no gate signal is applied. In this region SCR exhibits the reverse blocking characteristics similar to diode.

In this region the anode of the thyristor is made positive with respect to the cathode and no gate signal is applied to the thyristor. A small leakage current flow in this mode of operation of the thyristor.

By this type of triggering the device damages the scr. Hence a gate signal is applied before the forward break over voltage to trigger the scr.

After we had talked about that for a while, I brought the discussion back to the formula and the relationship between R, V and I: And what about this resistance in electricity then, do you measure that in some kind of unit?

Yes, in erm pause, c. Erm, an ohm is, the unit that resistance is measured in. It comes from ohm's law which is the erm formula that gives you resistance. That is erm pause, c.

### Current and voltage relationship in an electric motor | Physics Forums

Not sure about that? As Adrian considered resistance as slowing down or stopping current I thought he might be able to rationalise how a higher resistance would lead to less current for a particular potential difference 'voltage'. And the first circuit in order to get one amp of current to flow through the circuit. You have to adjust the power supply, until you had 10 volts.

So it took 10 volts to get one amp to flow through the circuit. And the second unclear the circuit, when you got up to 10 volts, there is still a lot less than one amp flowing. You can turn it up to 25 volts, and only when it got to 25 volts did you get one amp to flow through the circuit. Do you think those two circuits would have resistance? Erm pause, three seconds Probably yeah. No because they are not the same circuit, but - it would depend what components you had in your circuit, if you had different resistors in your circuit.

Yeah, I've got different resistors in these two circuits. Then yes each would have a different resistance. Can you tell me which one had the bigger resistance? Adrian's first response, that the circuits would 'probably' have resistance, seemed a little lacking in conviction. His subsequent responses suggested that although he knew there was a formula he did not seem to recognise that if different p. Rather he argued that different circuits would be likely to have different components which would lead to them having different resistances.

This was a weaker argument, as in principle two different circuits could have the same resistance.

I shifted my approach from discussing different voltages needed to produce the same current, to asking about circuits where the same potential difference would lead to different current flowing: Okay, let me, let me think of doing it a different way.

So yes okay so the power supply is 10 volts. And the other one also set on 10 volts, Okay. Any idea which has got the high resistance now?

• Electronics - Resistance and Power
• Power Electronics Interview Questions & Answers
• Basic electrical quantities: current, voltage, power

The second would have the higher resistance. Why do you say that? This time Adrian adopted the kind of logic one would hope a physics student would take. It was possible that this outcome was less about the different format of the two questions, and simply that Adrian had had time to adjust to thinking about how resistance might be linked to current and voltage.

You seem pretty sure about that, does that make sense to you?

Yes, it makes sense when you put it like that. Right, but when I had it the other way, the same current through both, and one required 10 volts and one required 25 volts to get the same current. You did not seem to be too convinced about that way of looking at it.

I suppose I have just thought about it more. Having made progress with the fixed p.