Calculate all the equations for current, voltage, resistance, power
1. The current and voltage of the series circuit are in the following laws: (such as: R1, R2 in series)
(1) Current: I=I1=I2 (the current is equal everywhere in the series circuit)
(2) Voltage: U=U1+U2 (total voltage is equal to the sum of voltages everywhere)
(3) Resistance: R=R1+R2 (total resistance is equal to the sum of each resistance) If n resistors with the same resistance value are connected in series, there is a total R=nR
2. The parallel circuit current and voltage have the following laws: (such as: R1, R2 in parallel)
(1) Current: I=I1+I2 (trunk current is equal to the sum of the currents of each branch)
(2) Voltage: U=U1=U2 (the trunk voltage is equal to the voltage of each branch)
(3) Resistance: (the reciprocal of the total resistance is equal to the reciprocal sum of each parallel resistance) or If n resistors with the same resistance value are connected in parallel, there is R total = R
Note: The total resistance of the parallel circuit is smaller than the resistance of either branch. Electrical work calculation formula: W=UIt (unit W in the formula→ focal point (J); U→ volts (V); I→ An (A); t→s).
5. Pay attention to the following when calculating electrical work using W=UIt:
(1) The W, U, I, and t in the equation are in the same circuit; (2) The unit should be unified when calculating; (3) It is known that any three quantities can find the fourth quantity.
6. The following formulas can also be used to calculate electric work: (1) Commonly used electric work formulas are: W=I2Rt, W=U2Rt, W=Pt and other formulas; （2）1kWh=1000W×3600s=3.6×106J； So the answer is: W=UIt; 3.6×106．
