A pulse-width modulation (PWM) inverter provides an output waveform that can have ___________

Ans. to #1

A

Ans. to #2

An island occurs when sections of the grid are disconnected from other sections, leaving one small section as the only section that is powered. In this case, the electrical power in the island typically is not strong enough to provide practical power to all customers in that section. Solar photovoltaic panels typically have anti-islanding circuits in them to protect from this condition.

Ans. to #3

The linear power supply uses a transformer and a four-diode full-wave bridge rectifier to produce the pulsing DC output waveforms. A capacitor is used as a filter to smooth out the DC. The remainder of the circuit contains a regulator and the load. The regulator is the part of the circuit that makes a linear power supply different from the newer switch-mode power supplies. The linear power efficiency is quite poor, in the range of 30 to 40.

Switch-mode power supplies

Ans. to #4

A change in the level of voltage magnitude that is sudden and unexpected.
A change in system frequency caused by one or more generation sources.
A sudden increase in active output power (kW) well beyond the typical level that would indicate a short
circuit somewhere in the system.
A change in power factor or reactive output power

Ans. to #5

An inverter is used to convert DC but a power to AC electrical power.

Ans. to #6

M is for Million 1,000,000
k is for thousand 1,000
m is for milli 1/1000

Ans. to #7

Turn off all electrical power to the component your are measuring.
Isolate the component on at least one terminal so that you do not read back into the circuit and measure resistance to other components.
Start with the meter on the highest resistance range and continually lower the range until you get the reading with the most accuracy.

Ans. to #8

B