Written by: Eng.Omar Abd-Elrahman
Before starting in our first topic
What is the current??
Generally current means the flow of molecules “we can call the water in a River a current of water so on “
Specifically:-
Current is the flow of carriers through any medium
“Carriers mean electrons or holes or even both “
First topic
We can connect any circuit using 2 ways the first is series and the second is parallel
What is the meaning of series??
Series means that we will connect all circuit components in series and there will be one current in the circuit and there will be a voltage drop in the elements “the voltage depends on the value of resistance or capacitance or inductance “
Notice
Series connection might be a part of circuit
The Figure present what I meant
We can calculate the current in this circuit using the law
V=I*Rtotal
Rtotal=R1+R2+R3
V1!=V2!=V3 as they have different values of res and the same value of current
What is the meaning of connecting component in a parallel way??
Connecting elements in a parallel way means that we will divide the current in the approaches and every approach will have a specific current it can be the same or not but the voltage in this approaches will be constant and current depends on the elements in the approach
When we can say that these elements are parallel??
We can say that elements are parallel if the elements start with the same point and end with the same point
Notice
Parallel connection might be a part of circuit
The Figure will Represent what I meant
Every approach of these approaches have the same value of voltage which equal 9 voltage
The current I1 !=I2 !=I3 We can calculate total current by calculating total Res Then from the law V=IR calculate I ..I1 &I2 &I2 ….I1 =9/R1 and so
After knowing all types of connecting elements in any circuit
Here we will talk about Ohm’s law
Ohm’s law talk about the relation between current and resistance and voltage
V=IR
Symbol Term
-I “current “
-V “voltage”
-R “Resistance”
From The relation we can notice that the relation between voltage and current is a directly relation & The same with Resistance
If we have a constant value of voltage and a Potentiometer “variable resistance “if we decrease R I will increase
Increasing R means Decreasing I
If we do an experiment in a lab using
1- power supply “voltage source “
2- Resistance “Potentiometer “
3- Voltmeter
4- Ammeter
We will take a Voltage from power supply about 10V
And change the values of Res and measuring I .V &R
We will notice the relation will not be constant because there will be a small voltage drop in the “internal resistance of voltmeter &ammeter “
This figure Represent the relation between voltage and current and resistance
Task
a-You have a Led “Light Emitting Diode “and a battery 6 volt and a resistance 330 ohm ...
1-semulate the circuit using proteus
2-do it in a test board
b-you have 3 Resistance 330 ohm and 2 res 1k connect them in parallel and In series
1-semulate the circuit using proteus and get the values of current and voltage drop in res
2-do it in a test board and measure the values of current and voltage
drop in res
Before starting in our first topic
What is the current??
Generally current means the flow of molecules “we can call the water in a River a current of water so on “
Specifically:-
Current is the flow of carriers through any medium
“Carriers mean electrons or holes or even both “
First topic
We can connect any circuit using 2 ways the first is series and the second is parallel
What is the meaning of series??
Series means that we will connect all circuit components in series and there will be one current in the circuit and there will be a voltage drop in the elements “the voltage depends on the value of resistance or capacitance or inductance “
Notice
Series connection might be a part of circuit
The Figure present what I meant
We can calculate the current in this circuit using the law
V=I*Rtotal
Rtotal=R1+R2+R3
V1!=V2!=V3 as they have different values of res and the same value of current
What is the meaning of connecting component in a parallel way??
Connecting elements in a parallel way means that we will divide the current in the approaches and every approach will have a specific current it can be the same or not but the voltage in this approaches will be constant and current depends on the elements in the approach
When we can say that these elements are parallel??
We can say that elements are parallel if the elements start with the same point and end with the same point
Notice
Parallel connection might be a part of circuit
The Figure will Represent what I meant
Every approach of these approaches have the same value of voltage which equal 9 voltage
The current I1 !=I2 !=I3 We can calculate total current by calculating total Res Then from the law V=IR calculate I ..I1 &I2 &I2 ….I1 =9/R1 and so
After knowing all types of connecting elements in any circuit
Here we will talk about Ohm’s law
Ohm’s law talk about the relation between current and resistance and voltage
V=IR
Symbol Term
-I “current “
-V “voltage”
-R “Resistance”
From The relation we can notice that the relation between voltage and current is a directly relation & The same with Resistance
If we have a constant value of voltage and a Potentiometer “variable resistance “if we decrease R I will increase
Increasing R means Decreasing I
If we do an experiment in a lab using
1- power supply “voltage source “
2- Resistance “Potentiometer “
3- Voltmeter
4- Ammeter
We will take a Voltage from power supply about 10V
And change the values of Res and measuring I .V &R
We will notice the relation will not be constant because there will be a small voltage drop in the “internal resistance of voltmeter &ammeter “
This figure Represent the relation between voltage and current and resistance
Task
a-You have a Led “Light Emitting Diode “and a battery 6 volt and a resistance 330 ohm ...
1-semulate the circuit using proteus
2-do it in a test board
b-you have 3 Resistance 330 ohm and 2 res 1k connect them in parallel and In series
1-semulate the circuit using proteus and get the values of current and voltage drop in res
2-do it in a test board and measure the values of current and voltage
drop in res
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