Resistorid

Resistorid are passive two-terminal electronic components that provide a defined resistance to current flow. They are used to set signal levels, limit current, divide voltages, bias active devices, terminate transmission lines, and convert electrical energy into heat. In Estonian, resistors are referred to as resistorid, while in English they are called resistors.

Fixed resistorid come in several materials and constructions, including carbon film, carbon composition, metal film, and metal oxide. They are designed to maintain a nearly constant resistance over a wide range of operating conditions. High-wattage versions, such as wirewound resistors, handle greater power and can tolerate higher temperatures. Variable resistorid include potentiometers, rheostats, and trimmers, which adjust resistance manually or automatically in a circuit.

Nonlinear and environment-sensitive resistorid include thermistors (NTC and PTC) and photoresistors (LDR). These components change resistance with temperature or light and are used in sensors and control circuits. However, they behave differently from fixed resistors, so circuit design must account for their characteristics.

Values and markings: resistance is measured in ohms (Ω). Many axial resistorid use a color-code or numeric markings to indicate value and tolerance. Standard value sets, known as E-series (E6, E12, E24, etc.), guide the selection of common values. Tolerance indicates deviation from the nominal value, typically 1%, 2%, 5%, or 10%. Temperature coefficient describes how resistance changes with temperature.

Form factors and packaging: resistorid are available as through-hole axial components and surface-mmount devices (SMDs) in sizes such as 0402, 0603, 0805, and 1206. They can also be found in resistor networks or arrays for compact, multi-resistance circuits.

In circuits, resistorid are analyzed using Ohm's law (V = IR) and combinations in series and parallel to achieve desired equivalent resistance.