ELECTRICITY ELECTRICITY

D.C. stands for direct current D.C. stands for direct current which flows in one direction which flows in one direction

only (- to +)only (- to +)

A.C.stands for alternating A.C.stands for alternating current which changes current which changes direction 50 times per direction 50 times per

second.second.

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D.C. is seen as a straight D.C. is seen as a straight line on the oscilloscope.line on the oscilloscope.

A.C. is seen as a wavey A.C. is seen as a wavey line on the oscilloscope.line on the oscilloscope.

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An electric current is a An electric current is a flow of charged particles flow of charged particles

called electrons.called electrons.You will see the circuit You will see the circuit

symbols on the side symbols on the side wall.wall.

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Current has the symbol I and is Current has the symbol I and is measured in amps (A)measured in amps (A)

Resistance has the symbol R Resistance has the symbol R

and is measured in ohms (and is measured in ohms (Voltage has the symbol V Voltage has the symbol V

and is measured in and is measured in volts(V)volts(V)

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Current is measured Current is measured with an ammeter in with an ammeter in

series.series. Voltage is measured Voltage is measured

with a voltmeter in with a voltmeter in parallel.parallel.

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V = IxRV = IxR

V

I R