Electronic – Resistance/Voltage relation in Rheostat

ohms-lawpotentiometerresistancerheostatvoltage

According to "How Computers Work" (Tenth Edition) by Ron White, he features a graphic of a potentiometer with three terminals on the bottom with the one on the left being for current flowing in and the center terminal connected to a wiper for current flowing out.

In the written explanation, Ron describes that "When the knob is turned clockwise, the electricity has less wire to travel through so that the resulting current is stronger and the volume is louder."

This confuses me as the graphic appears to show more resistance wire being used as the wiper is turned clockwise. Wouldn't the voltage decrease as you increased the amount of resistance? I obviously am a complete novice in terms of electrical engineering or else I would not be reading this book. Please help if you can. Thanks!

Best Answer

I'm not familiar with that book, but it sounds like he is describing a potentiometer used as a volume control.

The pot would be connected like so:

schematic

simulate this circuit – Schematic created using CircuitLab

Turning the pot clockwise will move the wiper upwards. In this application, the pot can be considered as a voltage divider. As you turn the pot clockwise, the upper resistor of the voltage divider reduces in value, while the lower resistor increases in value, so the output voltage (and the volume) increases.