The unit of resistance is called the Ohm, which is usually shortened to Ω the Greek letter Omega. Because an Ohm is a low value of resistance (it doesn't resist much at all), we also give the values of resistors in kΩ (1000 Ω) and MΩ (1000,000 Ω). These are called kilo-ohms and mega-ohms.
In this lesson, we are going to use four different values of resistor, 270Ω, 470Ω, 2.2kΩ and 10kΩ. These resistors all look the same, except that they have different colored stripes on them. These stripes tell you the value of the resistor.
The resistor color code works like this, for resistors like this with three colored stripes and then a gold stripe at one end.
Each color has a number, as follows:
- Black 0
- Brown 1
- Red 2
- Orange 3
- Yellow 4
- Green 5
- Blue 6
- Purple 7
- Gray 8
- White 9
A resistor with stripes brown, black, orange is 10 and three zeros so 10,000 Ω in other words 10 kΩ.
Unlike LEDs, resistors do not have a positive and negative lead. They can be connected either way around.