What is resistance?
Resistance is the opposition that a substance offers to the flow of
electric current. It is represented by the uppercase letter R. The
standard unit of resistance is the ohm, sometimes written out as a
word, and sometimes symbolized by the uppercase Greek letter
omega Ω.
What material is used to make resistance?
The alloys such as:
manganin(an alloy of typically 84.2% copper, 12.1% manganese,
and 3.7% nickel. It was first developed by Edward Weston in 1892),
constantan(an alloy of 55% Copper and 45% Nickel) or
nichrome (also known as NiCr, nickel-chromium or chromium-nickel
is a family of alloys of nickel and chromium) are used for making
standard resistance. For the reasons that they possess high
resistivity and low temperature co. efficient of resistance.
Who first invented the resistor?
Physicist Georg Simon Ohm
Electrical resistance was first discovered and formulated by
German physicist Georg Simon Ohm in 1827. Ohm's
groundbreaking work, Ohm's Law, laid the foundation for
understanding the relationship between voltage, current, and
resistance in electrical circuits.
Difference between dc resistance and ac resistance
AC resistance, also known as impedance, is the resistance to the
flow of alternating current and is a complex quantity that is affected
by frequency, material, and dimensions of the conductor. DC
resistance is the resistance to the flow of direct current and is
measured in ohms.
What is a Varistor? A varistor is a voltage dependent resistor
(VDR).
https://www.wellpcb.com/blog/components/uses-of-resistor/
Who invented rheostat?
Charles Wheatstone
Charles Wheatstone, a British inventor/scientist, is often credited
with developing the rheostat during the 19th century.
What is a variable resistance?
Definition of a Variable Resistor
As the name suggests, the variable resistor is a passive(A passive
element is an electrical component that does not generate power,
but instead dissipates, stores, and/or releases it. ), three terminal
device that can adjust its resistance via third terminal located
between two terminals so that the obstruction to the flow of current
goes up and down.