Rheostats are variable resistors used to control things like volume or brightness. They come in different types including wire wound, carbon, and trimpot models with linear or logarithmic tracks ranging from 100 ohms to 50,000 ohms. The document provides examples of resistance values and track types for common rheostat models.

1. Rheostats

12. 4K7 LIN means 4.7kΩ linear track
1M LOG means 1MΩ logarithmic track

13. Wire Wound Linear 5R to 10k 3
Carbon Linear 500R to 2M 1/2
Carbon Log 10k to 50K 1/2
Trimpot Linear 100R to 2M 1/2