Hello everyone, today I want to talk on resistance.
Resistance can be defined as the opposition of electric flow. It is measured in ohms. A material used to resist electric flow is a resistor.
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OHMS LAW
Ohms Law states that the flow of electric charge is directly proportional to it's potential difference. Provided that the temperature and every other physical quantities remain constant. The representative symbol is Ω.
Types of Electric Connection
There are 2 types of electric connection
- Series connection
- Parallel connection
Explanation
Series connection;
This is a straight connection. The power flowing through them are the same. The formula is R1+R2+R3…
Let's solve a problem as example
5 resistance of 12Ω are connected to a circuit. Calculate the Resistance.
Solution
=R1+R2+R3+R4+R5
=12+12+12+12+12
=60Ω
Parallel connection;
These connections are always parallel. The power flowing through them are not the same. The formula is 1÷R1+1÷R2+1÷R3…
Let's solve a problem as example
10 resistors of 30Ω each are connected to a circuit. Calculate the resistance.
Solution
= 1÷R1+1÷R2+1÷R3…1÷R10
= 1÷30+1÷30+1÷30…1÷30
= 10÷300
= 30
Ohmic and Non-ohmic substances
Ohmic substances are those substances that obey law
Example;
Metals
Resistors
Nichrome wire.
Non-ohmic substances are those substances that does not obey ohmic law.
Examples;
Semiconductor
Electrolytes
More calculations on resistances
Calculate the series and parallel resistance of the connection above.
As we know, if you straighten the wire,it will be;
So we will start by calculating the series connection
Solutions
R1+R2+43.
1+2+1
4Ω for series connection
1÷R1+1÷R2+1÷R3
1÷2+1÷2
2÷4
2Ω
Now to get the whole resistance, we add the series connection with the parallel connection. We have;
6Ω
That is the resistance of that connection.
Calculate the series and parallel resistance of that connection.
Remember to always straighten the connection and after find the series connection before the parallel connection. There we have;
Solution
R1+R2+R3…
5+20+15+5+5
50Ω for series connection
1÷R1+1÷R2+1÷R3…
1÷20+1÷20+1÷10+1÷15+1÷5
6÷80
13.33Ω
I'll stop here for now. Thanks for stopping by ❤️❤️❤️