LAB#4

A dc-source has positive and negative polarities. Is it correct to say that an ac-voltage source has no polarity? Why or why not?

please write introduction about AC Circuits and Parallel Circuits

electrical engineering what is current transformers advantage?

The exciting current of an electromagnet is rated at 12 amperes. When connected across a 122 - volt source the current is 14 amperes. Determine the ohms in a resistor which must be connected in series to limit the current to (a) rated value, and (b) 9 amperes.

a) Graphically show the differences between alternating current voltage (A.C) and direct current voltage (D.C). What are the advantages of A.C compared to D.C?

Can we select components voltage references randomly in order to write KVL? Why?

What will happen to the value of the impedance if the resistance will be increased or decreased? Explain...

An RLC series circuit connected to a 110 – volt and 50 – cycle AC source, contains the following series resistances and reactances: R1 = 10 ohm, R2 = 15, R3 = 5 ohms, XL1 = 20 ohms, XL2 = 25 ohms, XC = 40 ohms. Find the following: a.) EQUIVALENT REACTANCE b.) TOTAL IMPEDANCE c.) VOLTAGE DROP ACROSS THE CAPACITOR d.) TOTAL INDUCTANCE IN MILLIHENRY e.) TOTAL CURRENT f.) REACTIVE POWER g.) REAL POWER DRAW THE PHASOR DIAGRAM IF POSSIBLE AND ROUND OFF TO FOUR DECIMAL PLACES

How open circuit test can be performed? Which type of losses can be found using this test? Subject Electrical machine

what is ripple ? how to minimize the rippl , draw the circuit and show ??

Provide 3 sample calculations involving DC circuit under transient current condition on series R-L and Series R-C circuit? Need a simple supplementary explanation, can't quite understand the definitions I have currently.

Do we have a nonideal AC voltage source which means there is a resistance in it or only do we have a nonideal DC source?

Discuss causes of insulation failures in high voltage engineering. High voltage engineering

Problem A potentiometer is an instrument for measuring an unknown voltage in comparison to a standard voltage. In the potentiometer shown in Figure 1.0 a 16.0-m stretch of wire AB is connected to a 9.00-V battery. The resistance per unit length of the wire is 16.0 0/mm. The movable contact P is at point B. An ammeter (circle with A inside) is connected to point A. 16.0 m A B www Figure: 1.0 A V = 9.00 V

I need the answer as soon as possible

A 5-ohm resistor is connected in series with a 25 micro-farad capacitor. A source voltage of158 volts, 50 Hz supplies the combination. Determine the following:a. Circulating currentb. Voltage across the resistorc. Voltage across the capacitord. Real power supplied by the source

Q1. a) An SCR based AC power controller circuit is given in Figure 1. The circuit connects a 240V 50Hz AC source vi to a resistive load with resistance of 100. If the delay angle is a-15°, draw the waveforms of the load voltage Vo, and the voltage across SCR2. Calculate the power supplied to the load. + Vi Va + 2 SCR2 H₁₁ SCR₁ Figure 1 SCR based AC power control circuit Va + 2 io b) Figure 2 is a single phase 2-level voltage source converter (VSC) with a DC voltage Vd-200V. A PWM scheme, by comparing a reference value with a 10kHz triangle waveform, is used to control the switches S₁ and S2. The modulation index of the PWM is m=0.8. With the aid of graphs explain how pulse signals for the switches are generated, sketch the output voltage Vo, determine the duty cycle, and calculate the average output voltage. + Vo + Vo √ ₂ == Figure 2 A single phase VSC

A. Discuss the importance of power electronics interfaces in microgrid installations B. With the aid of diagram describe DC microgrid C. With the aid of diagram describe AC microgrid

use these two images to answer all these questions: What are the differences between ac and dc meters? Can you compare the value of the current in the load resistance for the same value of voltage with ac and dc supply? What is the function of the autotransformer in this circuit? Can you use an autotransformer to obtain variable output voltage from a fixed dc supply? What will happen if dc meters are used instead of ac meters in this circuit? What the difference between resistance and impedance is when referred to dc and ac measurements?

1- A). Which of the following could be used as a discharge device in an inductive AC circuit? a) resistor b) diode c) metal oxide varistor d) "a" and "c", not "b" B. What is the purpose of a discharge device used in conjunction with opening a highly inductive circuit? a) to minimize the possibility of damage to the circuits insulation as a result of a high induced voltage b) to minimize the possibility of endangering the life of the person opening the controlling switch c) to allow the magnetic field to gradually collapse, thus limiting the value of the self-induced ernf d) all of the above C. The high voltage induced by an inductor when its circuit is opened could be used constructively for a) an automotive ignition system b) an electric fence c) both "a" and "b" d) neither "a" nor "b"

Questions: 1. Are the experimental and theoretical values of voltages and currents match? Indicate the percentage of differences. 2. Give possible reasons for any discrepancies

What are the characteristics of an excellent DC power source? Give 3 and explain.

Can you solve the question step by step clearly ?