A component that stores electric charge and energy.
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What is capacitance measured in? Define this unit.
It is measured in Farads. A Farad is one coulomb per volt.
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Define Capacitance.
Charge stored per unit potential difference.
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How is a Capacitor charged?
It is connected up to a voltage which pushes negative charge onto the -tive plate of the capacitor. The -tive charge is repelled from the +tive plate. This causes a p.d between the two plates. As pd inc current decreases.
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How would you find the Total Capacitance of capacitors in parallel?
Ctotal=C1+C2+C3...
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How would you find the Total Capacitance of capacitors in series?
1/Ctotal = 1/c1+1/c2+1/c3...
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Which side of the batter yis the negative terminal?
The shorter side.
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The area under what type of graph sjows the energy stored in a capacitor?
A p.d against charged stored graph.
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What are the three equations for energy stored by a capacitor?
1) E = ½ QV 2) E = ½ CV² 3) E = ½ Q² / C
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time it takes to charge or discharge a capacitor depends on two things:
The capacitance of the capacitor, The resistance of the circuit.
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What type of decay occurs when discharging a capactior and what does this mean?
Exponential decay, it meants that no matter the charge, it takes the same legnth of time for the chrage to halve.
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How is a capacitor discharged through a resistor?
The cap is connected to a resistor, the pd in the cap creates a current in the circuit. This current flows in the oppo dirrection to the charging current, causing a decrease in p.d. Once pd=0 in the cap, it is discharged.
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What are the two equations to find the voltage and charge of a capacitor after a certain time?
Q = Q0e ^ (- 1 / RC) V = V0e ^ (- 1 / RC)
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Define time constant.
The time taken for the charge/pd/charge to fall to 36.8% of it's initial value. It is found by RC and measured in seconds.
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3 examples of capacitors in everyday use.
1) radio/TV, 2) Computer backup supply. 3) A Lab power supply.
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Other cards in this set
Card 2
Front
What is capacitance measured in? Define this unit.
Back
It is measured in Farads. A Farad is one coulomb per volt.
Card 3
Front
Define Capacitance.
Back
Card 4
Front
How is a Capacitor charged?
Back
Card 5
Front
How would you find the Total Capacitance of capacitors in parallel?
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