1.4 KiB
What is electricity
Electricity is the flow of electric charge.
Atoms
Atoms are build up of Protons, Neutrons and Electron.
Electrons can escape the atom and bind to a new Atom.
Copper is used in wires because it has 29 Electrons, with one in the outer (Valence) Shell. This Atom can easily escape and switch places.
Ohms Law
V = I * R;
I = V / R;
Voltage
is like the pressure in Cable, it forces the Electrons to move.
Current
A cable with a lot of electrons flowing through it has a high current. A cable can only handle a specific type of current. When the current is to high, the cable breaks
Circuit
A electric circuit is a closed loop through which electrons flow.
How to find resistance of resistors in series?
Just add them up
How to find the resistance of resistors in parallel?
When each of the resistors provides a new way to reach ground, then
1/R = 1/R1 + 1/R2 + 1/R3;
Example:
R1 = 4 Ohm R2 = 5 Ohm R3 = 20 Ohm
1/R = 1/4 + 1/5 + 1/20; 1/R = 0.5 | * R; 1 = 0.5R | * 2; 2 = R;
10 Ohm 23 Ohm 17 Ohm
1/R = 0.20230179 | * R 1 = 0.20230179R | / 0.20230179 4.94 = R;
Test
Input: 50v Current: 2A Resistors: 19Ohm
Ohms Law = V = IR; 50 = 2(19+R); 50 = 38+2R | - 38; 12 = 2R; 6 = R;
R = V / I;
Ohms law only works for D/C and NOT A/C;
5V in
1/R = 1/100+1/1000; 1/R = 0.011; 1 = 0.011R; 90.90909 = R;
I = V / R; I = 5 / 90.909090 I = 0.055; I = 5.5mA