6.1  Capacitors

 

6.1.1  Capacitors

Learners should be able to demonstrate and apply their knowledge and understanding of:

 

(a) capacitance; C =Q/V  ; the unit farad

 

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(b) charging and discharging of a capacitor or capacitor plates with reference to the flow of electrons

 

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(c) total capacitance of two or more capacitors in series; 

 

(d) total capacitance of two or more capacitors in parallel; C = C1 + C2 + ...

 

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(e) (i) analysis of circuits containing capacitors, including resistors

 

(ii) techniques and procedures used to investigate capacitors in both series and parallel combinations using ammeters and voltmeters.

 

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6.1.2  Energy

 

Learners should be able to demonstrate and apply their knowledge and understanding of:

 

(a) p.d. –charge graph for a capacitor; energy stored is area under graph

 

(b) energy stored by capacitor;

 

(c) uses of capacitors as storage of energy

 

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6.1.3  Charging and discharging of capacitors

Learners should be able to demonstrate and apply their knowledge and understanding of:

 

(a) (i) charging and discharging capacitor through a resistor

 

(ii) techniques and procedures to investigate the charge and the discharge of a capacitor using both meters and data-loggers

 

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(b) time constant of a capacitor–resistor circuit;

 

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(c) equations of the form      and   for capacitor–resistor circuits

 

The x in this equation can stand for the current, voltage or charge.  The form of the equation stays the same.

 

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(d) graphical methods and spreadsheet modelling of the equation      for a discharging capacitor

 

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(e) exponential decay graph; constant-ratio property of such a graph.

 

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