Electronics: An Online Guide for Beginners

Back || Resistors | Capacitors | Diodes | Transistors | Integrated circuits |Switches

Resistors are one of the most commonly used components in electronics. As its name implies, resistors resist the flow of electrons. They are used to add resistance to a circuit.

The color bands around the resistors are color codes that tell you its resistance value. Recall that resistance is measured in ohms.

Black=0,Brown=1,Red=2,Orange=3,Yellow=4,Green=5,Blue=6,Violet=7,Gray=8,White=9,Gold = 5% tolerance,Silver = 10% tolerance

Resistor: Brown, Black, Orange. Value = 10000 ohm or 10k

The tolerance bands indicates the accuracy of the values. A 5% tolerance (gold band) for example, indicates that the resistor will be within 5% of its value. For most applications, a resistor within 5% tolerance should be sufficient.

To get the value of a resistor, hold the resistor so that the tolerance band is on the right.

The first two color bands from the left are the significant figures - simply write down the numbers represented by the colors. The third band is the multiplier - it tells you how many zeros to put after the significant figures. Put them all together and you have the value.

NOTE: There are resistors with more bands and other types for specific applications. However, 4 band resistors(the ones discussed here) are the most common and should work for most projects.

One last important note about resistors is their wattage rating. You should not use a 1/4 watt resistor in a circuit that has more than 1/4 watt of power flowing.

For example, it is NOT okay to use a 1/4 watt resistor in a 1/2 watt circuit. However, it is okay to use a 1/2 watt resistor in a 1/4 watt circuit.

Schematic symbol