Nickel Hydride No. 5 battery.Available formulas for non-pure resistance circuits

　　A non-pure resistance circuit is a circuit that, when energized, emits heat and performs other forms of work on the outside besides internal energy.

　　Generators, motors, electric fans, electrolyzers, etc., in addition to generating heat, also perform work on the outside, so these are non-pure resistance circuits.

　　Electric power calculation can only use W=UIt=pt. Electric power calculation can only use p=UI=W/t. Electric heating uses Q=I²Rt.

　　If there is only resistance in an AC circuit, the circuit is called a pure resistance circuit. Electric lamps, soldering irons, irons, etc., they just generate heat. You may have questions here. Since these electronic components only generate heat, why do electric lamps also emit light in addition to generating heat? Because the light energy of electric lamps is converted from heat, they are purely resistive circuits.

　　Common non-resistance circuits include long-distance transmission towers, electric motors, etc.

　　Their power can be calculated with p=UI=W/t, and electric heat can be calculated with Q=I²Rt.

　　Available formulas for non-pure resistance circuits

　　1. p=UI (empirical formula, suitable for any circuit)

　　2. p=W/t (definition formula, suitable for any circuit)

　　3. Q=I2Rt (Joule’s law, suitable for any circuit)

　　4. p=p1+p2+…+pn (suitable for any circuit)

　　5. W=UIt (empirical formula, suitable for any circuit)

　　6. p=I2R (composite formula, only suitable for pure resistance circuits)

　　7. p=U2/R (composite formula, only suitable for pure resistance circuits)

　　8. W=Q (empirical formula, only suitable for pure resistance circuits. W is the work done by the current flowing through the conductor, and Q is the heat generated by the current flowing through the conductor)

　　9. W=I2Rt (composite formula, only suitable for pure resistance circuits)

　　10. W=U2t/R (composite formula, only suitable for pure resistance circuits)

　　Problems with electric power and electric power in non-pure resistive circuits

　　From the perspective of energy conversion, a pure resistance circuit converts all electrical energy into heat energy, that is, electrical power is equal to electric heat. When a purely resistive circuit works, W=Q. In a non-pure resistance circuit, the current does work and converts electrical energy mainly into other forms of energy, but a part of the electrical energy is also converted into heat energy. At this time, the electrical power is greater than the electric heat. For example: W>Q in circuits that are not pure resistors, such as motor rotation, electric bells, batteries (charging), etc.

　　1. Electric power

　　2. Electric power

　　3. Electric heating

　　Taking an electric motor as an example, when students encounter a non-pure resistance circuit, they can remember the following formulas to answer the questions about the electrical energy consumed and the heat energy generated. Most of the electrical energy consumed by the motor during operation is converted into mechanical energy, and a small part is converted into thermal energy. Therefore, the following formula can be used to calculate the motor circuit.

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