MANUFACTURING: Two processes are used manufacturing.
Coated film: A mixture of carbon, filler and binder is coated on a ring of insulating material. The surface of the film is processed to minimize abrasion of the film by the sliding contact tap. The contact is of brass or phosphor bronze. The contact is sparing loaded against element.
Range of values 100 ohms to 10 mega ohm
Power rating 1/2W to 2.5W
Tolerance 20% for 100 ohms to 1 mega ohm
30% above 1 mega ohm
Voltage coefficient 0.005% volt
APPLICATIONS: These are used as present potentiometer in TV, in brightness and contrast control, radio and measuring instruments.