The document summarizes key concepts about voltage, current, and circuit components. It states that a cell's voltage measures its ability to drive current, and that voltages add when cells are connected in series. It describes how voltmeters are used to measure potential difference by connecting to circuit wires leading to a cell's positive terminal. It also discusses how resistance affects current, how components connect in series and parallel, and briefly introduces light-dependent resistors, diodes, and LEDs.

2. The Voltage of a Cell.
 The ability of a cell to drive a current is measured
by its voltage.
 The volt symbol “V”.
 When cells are arranged in series with the positive
terminal of one cell connected to the negative
terminal of the next cell, it can be calculated by
adding their voltages.

3. Measuring Voltage.

 The potential difference or voltage between two
points in a circuit is measured by a voltmeter.
 The voltmeter is connected into a circuit with its
positive terminal connected to a wire that leads
towards the positive terminal of the cell.

4.  In an ammeter, the wires are attached to either
side of the part of the circuit being tested.
 It is arranged in parallel with this part of the
circuit.
Measuring Voltage.

5. Ohm’s Law


6. Resistance
 The
material through which a current flows offers
some resistance to the moving electrons.
Small current with an
High resistance applied voltage
an
d
Large current with the
Low resistance
same voltage

7.  The wires connecting the components in a
circuit have a low resistance while wires in
filaments of the lamps has high resistance.
 When they connect in series their resistance
combine the same way as the voltages of
the cells in series – They add.

8. LAMPS AND CURRENT SIZE
The size of the current flowing can be
estimated by looking at the brightness of the
lamps.
The lamp will shine brighter with more power
and it will shine less when there is less power.
The lamp also shares it’s power with other
components in the circuit.

9. The ammeter reading varies in the following way. At points A and D the
readings are the same. At points B and C, if the lamps are identical the
readings will be the same and exactly half the readings at A and D. so if A
and D are 6.0 amps the readings at B and C will be 3.0 amps.
A D
C
B
The total of the readings of the ammeters at B and C is
always the same as the reading at A and D even if the
bulbs are not identical. For example: if the reading at A and
D is 5.0 amps and the reading at B is 3.0 amps then the
reading at C will be 2.0 amps.

10. LIGHT-DEPENDENT
RESISTOR
A light-dependent resistor (LDR) is made from 2 piece of
metal which are jointed together by a semiconductor.
Semiconductor is a material that has just a few
electrons which can move freely. When the LDR receives
light energy, more electrons are released in the
semiconductor, and the resistance of the LDR becomes
lower. When the amount of light shining on it reduced,
fewer electrons are released and the resistance
increases.
This is the
symbol for
LDR

11. Normal Bright
Dim

16. • Current can flow only in one direction.
• Used to control the direction of the flow of
a current through complicated circuits
(components in series and parallel).
• Have a band marked at one end.
• The symbol should be drawn with the
straight line facing the negative terminal of
the source of the current.

17. LED
• An LED is a semiconductor diode,
allowing a current to flow in only one
direction and it produces light.
• It can emit red, yellow and green light.
• In electronic circuits an LED performs the
same task more efficiently.

18. PRESENTED BY :
MASON
TASYA
PAWITRA
WILL

19. Thank you for listening and
paying attention 