Electrical Engineering All Engineering Career

Voltage-dependent resistors (varistors) are primarily used to suppress surges in electrical circuits.

Sparking occurs when a load is switched off because the circuit has high inductance.

Electric current passing through the circuit produces all of the above effects:

• Magnetic effect (creates a magnetic field around the conductor)
• Luminous effect (produces light, such as in incandescent bulbs)
• Thermal effect (generates heat, such as in resistive elements)

Insulating materials have the function of preventing a short circuit between conducting wires.

The resistance of a carbon filament lamp increases as the applied voltage increases. This phenomenon is known as the positive temperature coefficient of resistance exhibited by the filament material. As the temperature of the filament increases due to higher voltage, its resistance also increases.

The number of electrons in the outermost orbit of a carbon atom is 4.

A rheostat differs from a potentiometer in the respect that it has a higher wattage rating. Rheostats are designed to handle higher power levels compared to potentiometers, which are often used for signal level applications.

For testing appliances, the wattage of the test lamp should be low. This ensures that the test lamp does not draw excessive current from the appliance being tested and that it can safely indicate the presence of voltage without causing damage.

The rating of a fuse wire is always expressed in amperes.

The true statement is:

"A galvanometer with low resistance in series is an ammeter."

When a galvanometer is connected in series with a low resistance, it becomes an ammeter.