New Holland CX720 Repair Manual page 187

Switches can be as simple as that used to turn on an implement lamp or as complex as the ones used to operate the
starting and lighting systems. Checking the operation of switches is usually just a matter of testing for power going
into the switch and for power leaving the switch at the appropriate contacts when the switch is operated.
One of the most common type of switches is the pressure switch, a switch opened or closed by a fluid pressure. An
example of this type of switch is the charge pressure switch, a simple on/off device that opens (or closes) when oil
pressure rises or lowers past a preset value.
FLASHERS
Flashers work automatically to interrupt and connect the flow of current.
In the flasher, a heating element warms a bimetallic strip. The strip bends, breaking contact with the power source.
When it cools, the bimetallic strip once again makes contact and the process begins again.
RESISTANCE DEVICES
A number of electrical components alter or make use of electricity through their resistance to current flow. Resistors
are components which are generally used to regulate the supply of voltage and current to other electrical components.
In some cases, the purpose of resistance in an electrical circuit is to provide light or heat. Lamps and cigar lighters are
examples. Lamps convert electricity into light, and cigar lighters convert it into heat. Both lamps and lighters make
use of the same physical principle, that is Ohms Law.
DISTRIBUTION SYSTEMS - ELECTRICAL POWER SYSTEM
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