Electrical resistors play a central role in electrical engineering. Ultimately, there is no electronical component that can do without them. Also known as ohmic resistance, it defines the electrical voltage required to allow a certain electrical current to flow through an electrical conductor. Even though electrical resistance seems very simple in a first approximation, the components can be very complex.
Resistors come in a wide variety of shapes and physical properties. Resistors in chip form belong to the SMD types (Surface Mounted Devices). They are designed as resistor networks for high-voltage or high-frequency applications.
Resistors whose behaviour changes depending on the voltage are called varistors. These voltage-dependent resistors are usually used as overvoltage protection.
Thermistors, on the other hand, are temperature-dependent. They are available with negative (NTC) or positive (PTC) characteristics.