Types of Resistors - Color code

The simplest electronic component next to the insulated copper-wire is this Resistor. You know that wire itself is a resistor and longer the wire the higher the resistance. It starts in Micro-Ohms for thick short wires and goes to Milli-Ohms and even Ohms in very very long and thin wires. That is the reason copper is chosen.


   
Getting Started in Electronics

Resistors start from Wires to Wirewound Types. Carbon Film Resistors are most Common, Metal Film Resistors are more stable and accurate. We have now SMD types with lower power some are Laser Trimmed Types for accurate values. Resistors Arrays are used in Digital Circuits. Some tutors of mine are made into EE Web Widgets.  Analog Tutors and Digital Tutors

Gold has low contact resistance, an excellent conductor and corrosion resistant.Hence they use it in Connectors. Nickle has good wear and abrasion resistance, it finds application in switches. Nichrome an alloy has a high resistance and used in heaters.Carbon too is used in electrodes and bushes. When carbon or metal is coated as a thin film on a ceramic base/substrate, we have the Metal and Carbon Film Resistors.The thin film is cut and ground to get the resistor value close to what was needed. You can scrape the paint off a 1/2 Watt Resistor and experiment with a blade.

Wirewound resistors could be Copper or Manganin for shunts or low values and Ni-Cr for Higher Values. You cannot wind a 1 Mega-Ohm by the wire-wound method, it would be expensive and have high-inductance and you will need a very thin wire. MEMS may make such things possible without winding wires but Watts or Power Capability and Dielectric Withstand capacity or Voltage Rating will be very low.     

See an Example of Color Code Reading

1st band - 1st digit - Yellow = 4
2nd band - 2nd digit - Violet = 7

3rd band - Red = 2 (zeros)
Means Two Zeros Follow - 4700 ohms - 4.7 kilo ohms or 4k7 like in Philips Circuits.



For 4 banded ones, MFR 1% first 3 bands represent first three digits, and fourth band stands for the number of zeros that follow. 4.7k will be Yw VtBk Bn.

Right End Band is for tolerance

Brown Band 1% -- MFR Metal Film Resistor is used in Instrumentation Electronics.
Gold Band 5% -- CFR Carbon Film Resistor is common for Consumer Electronics.
Silver Stripe is 10%

 

Some Resistors in the Industry

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