BASIC ELECTRONICS - OD1633 - LESSON 1/TASK 1
There are many similar memory aid sentences that are known to experienced
technicians. An individual might find one of the other sentences easier to
There is still a good chance that a mistake may be made on a resistor's
color band. If a mistake is made on the first two significant colors, it
usually is not too serious. If a mistake is made on the third band, this is
more serious because the value is going to be at least 10 times too high or
too low. Some important points to remember about the third band are:
When the third band is...
Black, the resistor must be a value which is less than 100 Ohms.
Red, the resistor must he in hundreds of Ohms.
Orange, the resistor must be in thousands of Ohms.
Yellow, the resistor must be in hundreds of thousands of Ohms.
Green, the resistor must be in megohms.
Blue, the resistor must be in tens of megohms or more.
Red, orange, and yellow are the most common colors for the third band. If
this is kept in mind, the selection of resistors from a parts bin will be
easier and a lot of trouble can be avoided.
The fourth band, which is the tolerance band, usually does not present too
much of a problem. If there is no fourth band, it means that the resistor