Resistors

Lesson 2

Resistors

Resistor colour codes

Capacitors

Resistors

 Provide resistance to the flow of electrons

 Limit the flow of current

 Imagine squeezing a hose pipe, the amount of

water passing through the pipe will be less



 Can be rated by…

 Resistance - measured in Ohms (Ω)

 Tolerance (% of nominal value)

 Power Rating (Watts)



 Schematic Symbol…

Resistors – Types



 Fixed









 Variable (Potentiometer, Rheostat)

Resistors



Use the colours to work out

the value of the resistor 0 - black

1 - brown

2 - red

3 - orange

4 - yellow

5 - green

6 - blue

7 - purple

8 - grey

9 - white



gold - 5%

silver – 10%

0 - black

1 - brown

Resistors - Example 1 2 - red

3 - orange

4 - yellow

5 - green

6 - blue

7 - purple

8 - grey

9 - white



gold - 5%

silver – 10%

First number Tolerance

2

5%





6

Second number Number of 0’s Resistance = 260Ω

1 zero

Resistors – Example 2

First number Tolerance

3 0 - black

5%

1 - brown

2 - red

3 - orange

3

4 - yellow

Second number Number of 0’s

5 - green

2 zeros

6 - blue

7 - purple

8 - grey

 1st band: orange = 3 9 - white



 2nd band: orange = 3 gold - 5%

silver – 10%

 3rd band: red = 2 zeros

 4th band: gold = 5% Resistance = 3300Ω or 3.3 kΩ

More Examples 0 - black

1 - brown

2 - red

470000 Ω

3 - orange

470K Ω 4 - yellow

1000 Ω 5 - green

1K Ω 6 - blue

7 - purple

56 Ω 8 - grey

9 - white

1500 Ω

gold - 5%

1.5K Ω

33000 Ω silver – 10%



33K Ω

6400000 Ω

6.4M Ω







1000 Ω = 1KΩ

1000000 Ω = 1000K Ω =1M Ω

Resistors – 5 Band Colour Code

Resistors – Typical Power

Ratings

Capacitors

 Stores electric charge

 Two metal plates separated by an

insulator

 Different Designs

Capacitors

 Measured in Farads (F) but

generally not this large, usually:

 Micro Farad (µF) or pico farads (pf)





 Schematic Symbol….



or

Capacitors

 Slowly charges up until the voltage

is the same as the battery

 Can store the charge for a long time

or until a conductor is connected

across it

 Several uses

 AC to DC converter

 Timing circuits

 Radio receivers

Common Capacitor Types







Surface mount



Disc

Electrolytic – polarized









High Voltage

Questions:

 Use the colour code chart to complete these:

1st Number 2nd Number 3rd Number 4th Number Resistor Value



Red Blue Orange Silver



Green Black Brown Gold



Yellow Violet / Purple Black Gold



White Gray Red Silver



Orange Orange Yellow Gold



360 Ω ±5%



10 Ω ± 10%



4700 Ω ± 5%



5 Ω ± 10%



8000 Ω ± 5%



33000000 Ω ± 5%