GENERAL PHYSICS II Flashcards
Are simply passive device that can store an electrical charge on their plates when connected to voltage source
CAPACITORS
How many parallel conductive plates does capacitor have which are not connected or touching each other, but are electrically separated by insulating material.
2 two
What is called to the insulating layer between a capacitor plate
Dialectic
Capacitance value and voltage rating
Capacitors
Is the measure of a capacitors ability to store an electrical charge onto it’s two plates
Capacitance
Si unit of capacitance
Farad ( f )
Farad is named after the British physicist ?
Michael Faraday
mf ×10–³
Milifarad
µF ×10-⁶
Microfarad
nF ×10-⁹
Nanofarad
Smallest unit of capacitance
Picofarad
pF ×10-¹²
Picofarad
Formula of capacitance of a capacitor
C= e0 L²
——
d
Constant value of e0
8.85 × 10-¹² C²/ N.m²
Capacitance value and depends upon three main factors
- Surface area
- Distance
- Dialectric Material
The larger the area the greater the capacitance
Surface area
Between the two plates, the smaller the distance the greater the capacitance
Distance
The higher the permitivity of the dialectric the greater the capacitance
Dialectric material
Electric connections
Series and parallel capacitors
Definition of series capacitors
Consecutive capacitors
Definition of parallel capacitors
One plate of each capacitor is connected directly to one terminal of the source
Ctotal of series
All over one.
_____1____________
= ¹/c¹ + ¹/ c² + ¹/c³
Ctotal of series
Take the sum.
= C¹ + C² + C³
Q total of series
Same and identical
Q¹ = Q² = Q³
QTotal of parallel
Take the sum
= Q¹ + Q² + Q³
Vtotal
= V¹ + V² + V³
Sum of the voltage drop of each capacitor
Same computation for series and parallel
Vtotal
Movement or flow of the charge
Electric current
Analogy
Flow of water on the river
Si unit of electric current
Ampere ( A )
The Si unit of electric current is named after the physicist
André - Marie Ampere
1 ampere is equivalent to?
1 coulumb per second
1coulumb / 1 second
Symbol of electric current
I (caps i)
Symbol of dialectic constant
K
What will happen to the value of capacitance when inserting a dialectic material between plates of a capacitor?
Changes / increases
Good dialectrics
• Materials with large values of K.
• this are usually highly iconic, meaning that they contain positive and negative ions bound together.
Materials that are very iconic tend to have
Largest value of K
Materials that are NOT ICONIC tend to have
Smallest value of K
The actual value of the dialectric constant depends on the
Material
Series Circuit
- Closed circuit
- not common in homes
- Unreliable wirings
- bulbs are dependent with each other
Parallel Circuit
- Closed Circuit
- Commonly used in homes
- reliable wirings
- bulbs are INDEPENDENT
Path for transmitting electric current
Electric circuit
Parts of an electric circuit
- Battery / a generator
- Bulbs / Lamps
- key / Switch
- Wires
Primary sources of energy
Battery
Device that use current
Bulb
Control the circuit
Switch
Transmission lines
Wires
Incomplete path which means there is NO FLOW of current
Open Circuits
Complete path and THERE IS a FLOW OF CURRENT
Closed circuit
Three elements of electricity
Voltage, current, and resistance
The three elements follows the
Ohms law
Formula for resistance
R = I
__
V
Si unit of resistance
Ohms ( Ω )
The value of wires resistance depends on its
Composition, size, and shape
It is useful to define a quantity of p called resistivity, where the value of p depends on the
Material used to make the wire, but not on its shape and size
Regulate, limit and control the current flowing anywhere in a circuit
Resistor
Measurements of resistors value
Resistance
Si unit of resistor
Ohms
Ohms was named after the physicist
Georg Simon Ohm
Is a way of showing the value of a resistor
Resistor colour code
Band A
1st digit
Band b
2nd digit
Band c
Multiplier
Band D
Tolerance
Black
00 ×1
Brown
11×10
Red
2
Orange
3
Yellow
4
Green
5
Blue
6
Violet
7
Grey
8
White
9
Gold
-1
Silver
-2
Is the percentage of error in the resistors resistance
Tolerance
