what are the types of resisters?

Answer 1

If you are speaking of simple resistor materials, they are carbon and metal.

With regards to function, they can be fixed, variable or adjustable.

In the exotic class there are photo resistors and resistors that change value in response to some other phenomena, such as voltage or temperature

Answer 2

As above, there many, and in most of which, the resistive material is either carbon, metal, or semiconductor. The list below is about in order of "commoness".

1) resistor - generally refers to the type that has wires coming out of the ends for through-hole applications, is of carbon composition, 5% tolerance, and can handle 1/4 or 1/8 of a watt without burning up

1A) SMD resistor - SMD stands for "surface-mount device". Like above, but much smaller with no wires coming out from it. Instead, the ends have a metal coating that is solderable. Wattage depends on size. For example, the "0402 package" is 0.04" long by 0.02" wide as is generally good to 1/16 of a watt.

2) precision resistor - similiar to above but usually metal-film composition, with a tolerance of 1% or better

3) power resistor - 2 common types, one usually similiar to 1), but physically a little larger and able to handle 1 or 2 watts, and the other more like a larger version of 2), using either a metal film or metal wire as the resistive element, mostly above 2 watts

4) potentiometer - an adjustable resistor, usually has a thumbwheel or small screwdriver slot that moves a contact arm along a resistive material (either carbon for low wattage or metal for higher wattage). Old name was rheostat, which was wire construction.

5) varisistor - this is a semiconductor, the most commontype being the MOV (metallic-oxide varisistor), which has the property that, as voltage across it rises, its resistance decrease. These are useful for things like absorbing voltage spikes on the power line before they enter the componentry of your computer.


go to www.digikey.com and type "resistor" into the search field, you'll get a huge list of many specific types