# 9.9: Capacitors

• • Camosun College
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Capacitors (Figure $$\PageIndex{1}$$) are devices used to absorb and store electric current to prevent damage to components. These components are made of two-conductor plates with a non-conducting material between them. Capacitors will store energy if the circuit is broken and will remain charged until the circuit is restored. Figure $$\PageIndex{1}$$: (CC BY-NC-SA; BC Industry Training Authority)

Capacitors are useful for absorbing stray currents and preventing arcing across opening contacts. Variable capacitors are called trimmers or tuners and are used only in very sensitive circuits with low current flow.

Capacitors are also used to shift the phasing inside electric motors. Depending upon their application, this can give electric motors greater starting torque (Figure  $$\PageIndex{2}$$), increased efficiency, or both. Figure $$\PageIndex{2}$$: Start Capacitor (Elcap, CC0, via Wikimedia Commons)