Editing Battery eliminator circuit (section)

== Radio-controlled (RC) models ==
In an electric-powered [[radio-controlled model]], the BEC is typically part of the [[electronic speed control]] (ESC). BEC allows such a model to carry only one [[battery (electricity)|battery]] (the motive power battery) instead of two (motive power, and a separate battery to operate the RC equipment). A BEC-equipped ESC meant for airplane use often incorporates a [[low-voltage-cutoff]] (LVC) circuit which can sense the voltage drop caused when the battery has little charge left. It then cuts the power to the 'drive' [[electric motor|motor]] in order to provide the 'steering' [[servo (radio control)|servo]](s) with enough power to be able to bring the model safely back to the operator. The power to the propeller is cut but the operation of the control surfaces would be maintained in order to perform a [[dead-stick landing]]. Without this feature, all control would be lost when the battery expired, probably resulting in the destruction of the model. In some cases, the BEC is part of the radio control receiver, instead of being part of the ESC.

RC BECs in their simplest form use a linear fixed [[voltage regulator]] with its standard circuit suggested in the manufacturer's datasheet – usually the power supply of the receiver needs 5&nbsp;V. [[Low-dropout regulator|Low-dropout]] types are preferred – especially for batteries with only a few cells. For small models, 1.5 to 2 [[Ampere|A]] are enough; for mid-size models a 3&nbsp;A type needs to be considered{{cn|date=August 2020}}. BECs for large models have to provide current of 5&nbsp;A or more. In this case, a more complicated switching mode regulator should be used, as the switching mode BECs are more electrically efficient than linear regulator BECs. The power dissipation losses in a linear regulator BEC are a product of the difference between the target [[voltage]] of 5 volts and the voltage of the main battery multiplied by the required current. For example, take a 10-cell [[Nickel-metal hydride battery|NiMH]] accumulator with a normal voltage of 12 volts. With a peak current of 5&nbsp;A, the BEC will have losses of (12&nbsp;V − 5&nbsp;V) × 5&nbsp;A = 35&nbsp;W. With a linear regulator, these 35&nbsp;W will be converted to heat and so require a large heat sink. This is an efficiency of (5&nbsp;V / 12&nbsp;V) = 41.7%. However, a switching mode regulator with a buck step-down supply can achieve over 90% efficiency.<ref>Basic Concepts of Linear Regulator and Switching Mode Power Supplies - http://cds.linear.com/docs/en/application-note/AN140fa.pdf {{Webarchive|url=https://web.archive.org/web/20150612111515/http://cds.linear.com/docs/en/application-note/AN140fa.pdf |date=2015-06-12 }}</ref> In all cases, it is a good idea to mount some large [[capacitor]]s to buffer the regulated output. In large plane or ship models, another possibility is to buffer the [[power supply]] with a further capacitor near the actuators (servos).

More recent uses for RC BECs are converting higher-voltage lithium polymer battery packs to 12 V. This has occurred due to the increased popularity of camera equipment for [[First-person view (radio control)|FPV]] use. Several BEC manufacturers offer a BEC ([[voltage regulator]]) for this purpose and people may become confused as this is 'out of the ordinary' to use a BEC for a 12 V application.

BECs also come in several forms, SBEC & UBEC being the main variety. See [[Voltage regulator]]