Editing RL circuit (section)

==Introduction==
The fundamental [[Passivity (engineering)|passive]] [[linear]] circuit elements are the [[resistor]] (R), [[capacitor]] (C) and [[inductor]] (L). They can be combined to form the [[RC circuit]], the RL circuit, the [[LC circuit]] and the [[RLC circuit]], with the abbreviations indicating which components are used. These circuits exhibit important types of behaviour that are fundamental to [[analogue electronics]]. In particular, they are able to act as [[electronic filter#Passive filters|passive filters]]. 

Capacitors are usually preferred to inductors since they can be more easily manufactured and are generally physically smaller, particularly for higher values of components. But parasitic inductance may still be unavoidable.

Both RC and RL circuits form a single-pole filter. Depending on whether the reactive element (C or L) is in series with the load, or parallel with the load will dictate whether the filter is low-pass or high-pass.

Frequently RL circuits are used as [[DC power]] supplies for RF [[Amplifier|amplifiers]], where the inductor is used to pass DC bias current and block the RF getting back into the power supply.