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Resistors
Resistors limit the flow of electricity through part of the circuit. This can be used to control timing circuits, divide voltages in to smaller portions or protect devices that are sensitive to too much current.
Resistance is measured in Ohms (Ω),
kilohms (1,000=1kΩ) or
Megohms (1,000,000Ω =1MΩ)
Resistors can go in the circuit either way round. The value is marked on the device with a colour code (see right), or it can be measured with almost any multimeter.
A shorthand is often used to write the value of a resistor. For example:
“100R”=100Ω
“10k”=10kΩ
“4k7”=4.7kΩ
Some resistors used in these experiments:
100R – Brown, Black, Brown
220R – Red, Red, Brown
1k – Brown, Black, Red
10k – Brown, Black, Orange
100k – Brown, Black, Yellow
Georg Simon Ohm
(16 March 1789 – 6 July 1854)
Discovered the relationship between voltage and current in electrical circuits “Ohm's Law”.
Time for:
A resistor game!
Only for five band resistors!
Skip for four band resistors