Electrical Machines and Circuits

The earth wire (grounding wire) is connected to the outer metallic body of the appliance. This ensures that if any live wire accidentally touches the metal body, the current safely flows to earth through the earth wire, preventing electric shock. It is not connected to the fuse (which protects against overcurrent), the filament (the heating element), or short circuitry.

For AC power transmission, the RMS voltage in India is 220V. The peak voltage (maximum instantaneous value) is √2 times the RMS value, so peak = 220 × √2 = 220 × 1.414 = 311V approximately. This peak value represents the maximum voltage reached during each cycle of the alternating current waveform. 220V is the RMS (root mean square) voltage, which is the effective DC equivalent.

A rectifier converts alternating current (AC) to direct current (DC) by allowing current flow in only one direction, using diodes in various configurations (half-wave, full-wave, bridge). Transformers only change AC voltage levels, dynamos generate electricity, and oscillators produce AC signals.

If the circuit of the conductor is closed, then a current flows in the conductor due to the induced emf between the two ends. The current produced is called induced current.

The number of rotations produced in one second is called the frequency of the alternating current.

The process by which alternating current is converted into direct current is called full wave rectification.

AC power can be increased or decreased in voltage by using a transformer.

A term formerly used for direct current was galvanic current.

While checking a tester, it is recommended not to join its free ends for more than a few seconds because the cells of battery will drain very quickly.

An ignitron is a type of controlled rectifier dating from the 1930's.Ignitrons were long used as high-current rectifiers in major industrial and utility installations where thousands of amperes of AC current must be converted to DC, such as aluminum smelters.

Cross talk is caused due to the inductive coupling between two wires that are close to each other.

Yes, it is the correct answer.

Yes, it is the correct answer. This may happen if the insulation of the wires has come off due to wear and tear. This may cause a short circuit. This results in overcurrent.

Yes, it is correct.

A transformer changes AC voltage levels through electromagnetic induction between primary and secondary coils. It cannot work with DC current. Dynamos generate electricity, conductors transmit current, and inductors oppose current changes.