# Recent questions tagged current

Alternating current

A charge of 0.1 C moves past a given point every 0.01 s. How much is the current?

Describe the difference between direct and alternating current.

Explain why potential difference is necessary to produce current in a circuit.

A) Watt B) Volts C) Farad D) Ampere

Kirchhoff's current law

Current ratio

Current divider rule

Current formula

Capacitive current

How to find total impedance Z, current I and Impedance angle ?

Why inductor current lags inductor voltage ?

Explain lagging quantity and leading quantity, explain this concept with voltage and current waveform

List out any four effects of electric current used in measuring instruments & write name of meter working on it.

State various effects of electric current and explain any one.

Define: 1) voltage ratio, 2) current ratio, 3) transformation ratio of transformer.

Draw the Delta connected three phase system showing all the voltages and currents. Write the power equation.

Write the relation between phase and line current, phase and line voltage for Star connection.

A zener voltage regulator has load requirements of 12 V and 2 A. The zener diode minimum current requirement is 0.2 A. The minimum voltage at input is 24 V. What is the required value of series resistance with source? A) 5.45 Ω B) 6 Ω C) 7.2 Ω D) 6.38 Ω

If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be A) 0.98 B) 0.41 C) 59 D) 55

In a series R-C circuit, with the increase in frequency, current (A) Reduces (B) Increases (C) Does not change (D) Becomes zero

A 1000Ohm, 1 Watt resistor can safely pass a current of

The operating point of a protective current transformer is near the

If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be

Leakage current flows through the thyristor in

If the % reactance upto the fault point is 20%, then the short circuit current will be

Step-down transformer converts high voltage and low current into:  (A) How voltage and high current (B) High voltage and low current (C) Low voltage and high current (D) None of the above

Which of the following is the least expensive protection for over current in low voltage system?  (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker

A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is

The coefficient of reflection for current wave is

For a round wire, the approximate value of fusing current is given by

For arc welding current range is usually  (1) 10 to 15 A (2) 30 to 40 A (3) 50 to 100 A (4) 100 to 350 A

The skin effect in conductors is due to non uniform distribution of current in it and major portion of current is near the _______ of conductor.  (1) Surface (2) Center (3) Complete cross section area (4) Axis

In parallel RLC resonance circuit at resonance the current will be  (1) Minimum (2) Maximum (3) Zero (4) Infinite

The inrush current of a transformer at no load is maximum if the supply voltage is switched on  (1) at peak voltage value (2) at zero voltage value (3) at half voltage value (4) at 0.866 time voltage value

The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is :  (A) 256 W (B) 320 W (C) 500 W (D) 625 W

A current controlled voltage source is equivalent to :  (A) series voltage feed -back amplifier (B) shunt current feed -back amplifier (C) shunt voltage feed -back amplifier (D) series current feed -back amplifier

The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole)  (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents

A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

In a series RLC high Q circuit, the current peaks at a frequency  (1) equal to the resonant frequency (2) greater than the resonant frequency (3) less than the resonant frequency (4) equal to half the resonant frequency

Which of the following theorems enables a number of voltage (or current) source to be combined directly into a single voltage (or current) source. (1) compensation theorem (2) reciprocity theorem (3) superposition theorem (4) Millman's theorem

If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be

Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage  D) None of these

A network that consists of at least a voltage source or current source is called A) Active network B) Ideal network C) Sourced network D) Outsourced network

The current flow in a battery is due to ______ A) movement of ions B) movement of protons C) movement of holes D) movement of neutrons

In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized