1. Digital Multimeter (DMM)
Used to measure the following:
Voltage – DC and AC
Current – DC and AC
Resistance
Capacitance
Temperature – w/ extra probe
Also used to check:
Diodes
Transistors

2. We’ll Use the DMM to Measure Resistance
Resistors restrict the flow of current, given a fixed voltage
Unit = Ohms, Ω
They come in different packages

3. Color Code
The resistors we’ll test have a color code to identify their resistance and tolerance.

4. Resistor Color Band Code
Band 1 (closest to the end) – first digit
Band 2 – second digit
Band 3 – power of ten multiplier (most cases simply the number of zeros)
Band 4 – tolerance (Red = 2%, Gold = 5%, Silver = 10%, none = 20%)
Color
Value
Black
Brown
Red
Orange
Yellow 1 2 3 4
Green
Blue
Violet
Gray
White 5 6 7 8 9

5. What is “Tolerance” about?
If a resistor has a nominal value of 1000 Ω and a tolerance of ± 10 % then individual resistors with the same nominal value are allowed to vary in their actual values from 900 Ω to 1100 Ω and still be considered acceptable.
Any resistor fabricated with an actual value outside that range should be rejected as “not meeting specifications”.

6. Practice Problems
Determine the nominal value of resistance and the tolerance for resistors having the following color codes.
Brown Green Red Silver
Yellow Violet Orange Gold
Red Red Red
Determine the color code to specify each of the following resistors
1 kΩ
390 kΩ
56Ω