Briggs & Stratton 86262GS, Familiarization & Troubleshooting Manual

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Rectifiers
Rectifiers, also known as diodes, are used to convert
alternating current (AC) to direct current (DC). A simple
rectifier consists of a thin film of metallic oxide which is
deposited on a thicker plate of metal, such as iron. Selenium
is often used as the metallic oxide in a rectifier.
Rectifier Operation
A copper oxide rectifier is illustrated in Figure 2.38.
When alternating current is applied to the opposite faces of
the two discs, current can flow from the copper to the
copper oxide face; it cannot flow in the opposite direction.
The rectifier thus permits one alternating current to pass
but blocks the reverse alternation.This action results in a
“pulsating” direct current (DC) flow. A rectifier that allows
only one alternation of current to pass is called a “blocking”
diode or “half-wave” rectifier (Figure 2.39).
A “plug-in” type of bridge rectifier is shown in
Figure 2.40.
Notice that a varistor has been added to this rectifier, to
protect the diodes against voltage surges.
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Section 2 • Generator Components & Systems
Portable Generator Familiarization & Troubleshooting Guide
Figure 2.38 — Example Of Copper Oxide Rectifier
Figure 2.39 — Typical Blocking Diodes
Figure 2.40 — Plug-In Bridge Rectifier With Varistor