Capacitors
Magic of Electrons
© 2011 Project Lead The Way, Inc.
Capacitors
• Capacitors
• Charging the Capacitor
• Discharging the Capacitor
This presentation is intended to be used with Activity 6.2.5 Capacitors.
Capacitors
Capacitor: An electrical device used to
store electrical charge
Symbol for Circuit
Diagrams
or
Capacitors
Capacitors allow current
to flow through a circuit
as they fill with a charge.
_
DC
+
When the capacitor’s
voltage supply matches
the power source,
current stops flowing.
Capacitors
• Made of two layers of
conductor and a layer of
insulator.
• Electrolytic Capacitors
• Capacitance, measured in Farads (F)
– 1 F = 6.28 x 1018 electrons
– 1 µF = 6.28 x 1012 electrons
Capacitors
• Stored energy in the capacitor is released in a quick burst
unless slowed by resistance.
• Capacitors are found in almost all electronic devices.
– They store energy, provide quick bursts of power, even out power
if there is a small loss, etc.
• Capacitors are used for the flash in cameras.
Charging Circuit
Draw a schematic diagram of the following charging
circuit, which includes a capacitor, a push switch, a LED,
powered by a 6V DC power supply.
Just as an LED is polarity-sensitive, many capacitors are
too. Look for an indication on the capacitor to verify.
Discharging Circuit
Draw a schematic diagram of the discharging
circuit with a pushbutton switch, a LED, and a
place for the charged capacitor to be placed.
Will the polarity of the capacitor affect this
circuit? Explain.
Charging the Capacitor
Place the smallest capacitor in the circuit.
Push the switch, completing the circuit.
What did the LED do after the capacitor was
plugged in?
Discharging the Capacitor
Plug the capacitor into the discharge
circuit. Press the push switch.
What did the LED do?
Repeat the charge and discharge with the other
capacitors provided.
Image Resources
Microsoft, Inc. (2009). Clip Art. Retrieved January 22, 2009, from
http://office.microsoft.com/en-us/clipart/default.aspx