How to solve a circuit

How we calculate V,R and I in the following circuits?

• Rt, It, V1, V2 and V3 ?

1. Rt= R1+R2+R3 >> Rt= 10+20+30= 60Ω
2. It= Vt: Rt >> It= 180: 60= 3A
3. V1= R1x It>>V1= 10x3= 30v
4. V2= R2x It>>V2= 20x3= 60v
5. V3= R3x It>>V3= 30x3= 90v

• Rt, It, I1, I2 and I3 ?

1. Rt= 1:[(1:R1)+(1:R2)+(1:R3)]>> Rt= 1:[(1:15)+(1:5)+(1:10)]= 2.72Ω
2. It= Vt: Rt>> It=5: 2.72= 1.83A
3. I1= Vt: R1>> I1=5: 15= 0.33A
4. I2= Vt: R2>> I2=5: 5= 1A
5. I3= Vt: R3>> I3=5: 10= 0.5A

• Rt, Rtp, It, I1,I2,I3,I4 ?

1. Rtp= 1:[(1:R1)+(1:R2)+(1:R3)]>>                                          Rtp={1:[(1:3)+(1:6)+(1:3)]}=1.2Ω
2. Rt=R4+Rtp>> Rt=2+1.2=3.2Ω
3. It=Vt: Rt>> It=9: 3.2=2.8A
4. I1= Vt: R1>> I1=9: 3= 3A
5. I2= Vt: R2>> I2=9: 6=1.5A
6. I3= Vt: R3>>I3=9:3= 3A
7. I4=It>> I4=2.8A

Basics of electricity

WHAT IS ELECTRICITY?

• Electricity is the physical flow of electrons, referred as an electrical current. Electricity is an energy carrier that efficiently delivers the energy found in primary sources to end users, who convert it into energy services.

ELECTRIC CURRENT (I)

• Is the magnitude of an electric current measured by the quantity of electricity crossing a specified area of equipotential surface per unit time. 
• It is measure in Amperes (A).

VOLTAGE (V)

• The voltage, voltage or potential difference is the pressure exerted by a source of electrical power or electromotive force on electric charges or electrons in a closed electrical circuit, to establish the flow of an electric current.
• A greater potential difference or pressure exerted by a source on the electrical charges or electrons contained in a conductor, the greater the voltage or voltage in the circuit to which that conductor corresponds.
• It is measure in volts (v).

RESISTANCE (R)

• It is called electrical resistance, the difficulty or opposition of a body to the passage of an electric current to circulate through it.
• It is measure in ohms (Ω).

OHM`S LAW

• Georg Ohm found that, at a constant temperature, the electrical current flowing through a fixed linear resistance is directly proportional to the voltage applied across it, and also inversely proportional to the resistance. This relationship between the Voltage, Current and Resistance forms the basis of Ohm`s law.

1. To find the Voltage, ( V ) >> [ V = I x R ]   
2. To find the Current, ( I ) >> [ I = V ÷ R ]     
3. To find the Resistance, ( R ) >> [ R = V ÷ I ]