NA

2. VOLTAGE,
CURRENT,
AND

3. CURRENT: FLOW OF ELECTRIC CHARGES
DRIFT VELOCITY
 A type of movement of charges due to electric
potential energy, wherein electrons move from one
reference to another.
ELECTRIC CURRENT
 It is when the movement of electrons to any
direction is regulated and made to move
continuously in one direction.

4. Mathematically, electric current is computed using the
equation:
𝑰 =
𝒒
𝒕
Wherein:
I= electric current
q= amount of the charges passed
through a conductor
t= unit of time

5. EXAMPLE:
 Compute the current produced by a +6.5x1018 𝐶
charge flowing in 15 s.
 A steady current of 0.6 A flows through a wire. How
much charge passes through the wire in 1 minute?
q=It

6. RESISTANCE AND RESISTIVITY
ELECTRICAL CONDUCTOR
 Is any material that allows the free flow of electric
current

7. RESISTANCE AND RESISTIVITY
RESISTANCE
 The limitation to current flow of a conductor.

8. FACTORS EFFECT ON
RESISTANCE
EFFECT ON CURRENT
FLOW
ELECTRICAL RESISTIVITY
Increase Increase Decrease
Decrease Decrease Increase
ELECTRICAL CONDUCTIVITY
Higher Decrease Increase
Lower Increase Decrease
TEMPERATURE
Higher Increase Decrease
Lower Decrease Increase
LENGTH OF CONDUCTOR
Longer Increase Decrease
Shorter Decrease Increase
CROSS-SECTIONAL AREA OF
CONDUCTOR
Higher Decrease Increase
Lower Increase Decrease
Table 4.1 Factors that affects resistance and current flow.

9. RESISTANCE AND RESISTIVITY
ELECTRICAL RESISTIVITY
 It is an intrinsic property of the material that
describes how it resists the electric flowing.
ELECTRICAL CONDUCTIVITY
 An increase in the electrical conductivity of the
material.

10. Mathematically, resistance is computed using the equation:
R=
𝜌𝑳
𝑨
Wherein:
R= equivalent resistance
𝜌 = resistivity of conductor
L= length
A = cross-sectional area

11. EXAMPLE:
 Compute the resistance of a conductor given a resistivity
of 10.4 𝝮-m, length of 4 m, and cross sectional area of
7.85x103
𝑚2
 A conductor has a diameter of 2.59 mm. How many
meters of this material are needed to yield a
resistance of 1 𝝮? The resistivity of the conductor is
1.77x108 m
L=
𝑅𝝿𝐴2
𝞺

12. OHM’S LAW
 Georg Simon Ohm (1827) discovered the relationship
among voltage, current and resistance. He found out
that electricity acts similarly to a water pipe.
In the equation form, Ohm’s law is stated as follows:
V = IR

13. EXAMPLE:
 Using Ohm’s law, solve for the electric current of a
conductor given a voltage of 25 V and resistance of 10 𝝮.
 An electric heater uses 15 A of current when
plugged to a 220-V outlet. What is the resistance
provided by the appliance?

14. ELECTRIC CIRCUITS
 The pathway for the current to move and from the
source and the appliance.
 Allow the current to flow from the source of the current
to the load where the current is needed.
CLOSED CIRCUITS
OPEN CIRCUITS
 Have gap(s) where current cannot flow. Thus, electric
current cannot be delivered.

16. SCHEMATIC DIAGRAM
Table 4.2 Basic components of schematic diagrams of electric circuits

17. THE SERIES CIRCUIT
 All components are connected using a single pathway. It
is characterized by a single loop for the current flow.
𝑉𝑡𝑜𝑡𝑎𝑙 = 𝑉1 + 𝑉2 + 𝑉3 + ⋯ + 𝑉
𝑛
𝐼𝑡𝑜𝑡𝑎𝑙 = 𝐼1 = 𝐼2 = 𝐼3 = ⋯ = 𝐼𝑛
𝑅𝑡𝑜𝑡𝑎𝑙 = 𝑅1 + 𝑅2 + 𝑅3 + ⋯ + 𝑅𝑛

19. FORMULA:
𝑅𝑇𝑜𝑡𝑎𝑙 = 𝑅1 + 𝑅2
𝐼𝑇𝑜𝑡𝑎𝑙 =
𝑉𝑇𝑜𝑡𝑎𝑙
𝑅𝑇𝑜𝑡𝑎𝑙

20. THE PARALLEL CIRCUIT
 Use branches to allow current to pass through more
than one path, unlike in the series circuit.
𝑉𝑡𝑜𝑡𝑎𝑙 = 𝑉1 + 𝑉2 + 𝑉3 + ⋯ + 𝑉
𝑛
𝐼𝑡𝑜𝑡𝑎𝑙 = 𝐼1 = 𝐼2 = 𝐼3 = ⋯ = 𝐼𝑛
1
𝑅𝑡𝑜𝑡𝑎𝑙
=
1
𝑅1
+
1
𝑅2
+
1
𝑅3
+ ⋯ +
1
𝑅𝑛

22. FORMULA:
1
𝑅1𝑇𝑜𝑡𝑎𝑙
1
𝑅2𝑇𝑜𝑡𝑎𝑙
𝐼1 =
𝑉
𝑅
𝐼2 =
𝑉
𝑅
𝐼𝑇𝑜𝑡𝑎𝑙 =
𝑉𝑇𝑜𝑡𝑎𝑙
𝑅𝑇𝑜𝑡𝑎𝑙