Question

Ac and dc both can be measured by:

Answer 1

Ac and dc both can be measured by hot-wire instruments.

Hotwire instrument uses the heating effect of current for measuring the magnitude. The working principle behind hot wire instrument is that the length of the wire increases because of the heating effect of the current flowing through it.

Following are the advantages of hot wire instrument:

• The instrument is used for both AC as well as DC measurements.
• Hotwire instrument is not affected by the stray magnetic field.
• The calibration is the same for AC as well as DC measurements.
• The construction of the hot wire instrument is simple and cheap.

Following are the disadvantages of hot wire instrument:

• The response of the hot wire instrument is very slow.
• Power consumption is more.
• The instrument cannot withstand overload as well as mechanical shock.