Voltage Converters & Switches
A solar system's battery voltage can fluctuate depending on which stage of charging it's undergoing. This can damage some sensitive equipment if it's connected directly to the batteries. A voltage regulator for your boat or RV provides a way to stabilize the voltage from the power source.
A voltage converter converts a voltage down to the proper voltage needed to operate a device. A voltage converter can be used to convert a lower voltage to a higher voltage and a high voltage to a low voltage.
A voltage controlled switch is used when a voltage condition is needed to activate a switch. The switching function is really no different than a standard light switch, as far as function goes. It can open or close an electrical circuit.