Distribution Rules of resistance, current, voltage, power, electric power, and electric heating of series and parallel circuits

1. Power: (1) Definition: the number of electric resources contained in an object is expressed by the symbol "Q.
(2) unit: the colon (database), represented by the symbol "C.
(3) inspection: Electric Appliance (structure, principle, and use ).
2. Current: (1) Definition: the electric power passing through the cross-section of the conductor within 1 second is called the current intensity (current ). It is represented by the symbol "I.
(2) formula: In the I = Q/t (Definition) formula, I indicates the current intensity (current), Q indicates the electric usage through the cross section of the conductor, and t indicates the power-on time.
(3) units: international units-commonly used units of ampere (a)-Ma and μA ).
(4) Measurement: Current Meter.
(5) circuit features: In a series circuit, the current is equal everywhere, that is, I1 = I2 = I3 =... = In
In a parallel circuit, the current in the trunk path is equal to the sum of the current in each branch, that is, I Total = I1 + I2 +... + In
3. voltage: (1) effect of voltage: voltage is the reason for the formation of current by moving the free charge. It is represented by the symbol "U.
(2) Power Supply: the power supply generates voltage at both ends of the conductor. It is a device that provides voltage. It converts other forms of energy into electric energy, however, energy is converted into other forms of energy.
(3) units: Common units of international units-volt (v) include kilovolt (Kv), millivolt (MV), and microvolt (μV ).
(4) several voltage values: 1. the voltage of a Dry Battery u = 1.5 V
2. the voltage of each lead battery is u = 2 V
3. lighting circuit (Home Circuit) voltage U = 220 V
4. The safe voltage to the human body is no higher than 36 Volts (U ≤ 36 volts)
(5) Measurement: voltmeter.
(6) circuit features: the total voltage at both ends of the series circuit is equal to the sum of the voltage at both ends of each part of the circuit. That is, u = u1 + u2 +... + UN
In a parallel circuit, the voltage at both ends of each branch is equal. That is, u = U1 = U2 =... = UN
4. Resistance: (1) Definition: the obstruction of the conductor to the current is called resistance. It is represented by the symbol "R.
(2) units: Common units of the international Organization-Ohm (euro) (Ω) include qianniu (kΩ) and MΩ ).
(3) factors determining the resistance size: the resistance of a conductor is a kind of nature. Its size depends on the length, cross-sectional area, and material of the conductor. The resistance of the conductor is also related to the temperature.
(4) Measurement: voltammetry (voltmeter and ammeter ).
(5) equivalent resistance: A. The total resistance of a series circuit is equal to the sum of the resistance of each series conductor. That is, r Total = R1 + r2 +... + Rn if each resistor is R, R = nR
B. the reciprocal of the total resistance of a parallel circuit is the sum of the reciprocal of each parallel resistance. That is, 1/r = 1/R1 + 1/r2 +... + 1/RN
If the resistance of each parallel conductor is R, 1/r = N/R: r = r/n
5. Electrical Power: (1) Definition: the power of a current through a circuit is called electrical power, represented by the symbol "W.
(2) essence: The process of current work is essentially the process of converting electric energy into other forms of energy. How much power is done by current, how much power is converted into other forms of energy, and how much power is consumed.
(3) Unit: international unit-Jose (Jose) (j)
Other units-kWh (kWh), also expressed in "degree" in life.
(4) formula: defined formula -- W = uit = PT export formula -- W = i2rt W = (U2/R) t w = uq (Q indicates the power here)
(5) Measurement: use an electric energy meter. Measure the test taker's knowledge about its reading method (the last digit is a decimal number ).
On the Power Meter nameplate, the following content is often used: "220v", indicating that the rated voltage of the Power Meter is 220 V.
"5A" -- indicates that the maximum current allowed by the electric energy meter is 5.
"KWh" -- indicates the unit of electrical power, that is, "degree" "3000r/kWh" -- indicates that the turntable of the Electric Energy Meter turns around 3000 for every 1 degree of electricity consumption.
(6) electrical features:
A. Electrical Power Characteristics: In a series circuit and a parallel circuit, the total power of current is equal to the sum of current work of each part of the electric appliance. That is, W Total = W1 + W2
B. Power Distribution in a Series Circuit: In a series circuit, the power of the current through each resistor is proportional to its resistance, that is, W1: W2 = R1: r2
C. Distribution of power in a parallel circuit: In a parallel circuit, the power of the current through each resistor is inversely proportional to the resistance, that is, W1: W2 = R2: r1
6. Electric Power: (1) Definition: The power of current in a unit of time is called electric power. It is represented by the symbol "p. Meaning: it is a physical quantity that represents the speed of current work.
(2) units: international units-commonly used units of Watt (w)-kw)
(3) formula: defined formula -- p = W/T deciding formula-P = UI (because w = uit = pt) export formula -- p = u2/r = i2r (Because p = UI, I = u/R, u = IR)
(4) measurement: The voltammetry (voltmeter and ammeter) can also be measured by Electric Energy Meter and stopwatch.
(5) rated power and actual power: the electric nameplate is usually labeled with rated voltage and rated power. If a lamp is labeled as "PZ220-60", "220 V 60 W", you need to know from the R (Because p = u2/r so r = u2/P ), you can also find the current I when the lamp is working normally (Because p = UI, I = P/U ). The actual power of a light is determined by its brightness and darkness.
(6) electric power features:
A. Electric power characteristics: the total power consumed by the series circuit and the parallel circuit is equal to the sum of power consumed by each electric appliance. That is, total P = p1 + p2
B. Relationship between power and resistance in a Series Circuit: The power consumed by each electrical appliance (resistor) in a series circuit is proportional to its resistance. That is, P1/P2 = R1/R2
C. Relationship between power and resistance in a parallel circuit: The power consumed by each electrical appliance (resistor) in a parallel circuit is inversely proportional to its resistance. That is, P1/P2 = R2/r1
7. Electric Heating: (1) Definitions: The heat generated when the current passes through the conductor is called electric heating. That is, the thermal effect of current. It is represented by the symbol "Q.
(2) Unit: international unit-Jose (Jose) (j)
(3) formula: the premise for the establishment of the definition formula q = i2rt (Jiao er's law) Export formula q = W = uit q = (U2/R) T is, the circuit is a pure resistance circuit, that is, when the current passes through the conductor, all the electric energy is converted to internal energy, but not to other forms of energy at the same time, that is, the power of current is used to generate heat.
(4) Electric Heater heating body-large resistivity, high melting point. Fuse-lead-antimony alloy wire with large resistivity and low melting point.
(5) electric heating features:
A. electric heating characteristics: whether it is a series circuit or a parallel circuit, the total heat produced in the circuit is equal to the total heat produced by each electric appliance. Q Total = Q1 + q2
B. Relationship between electric heating and resistance in the series circuit: The Electric Heating generated by each electrical appliance (resistance) in the series circuit is proportional to its resistance. Q1/q2 = R1/R2
C. Relationship between current heat and resistance in the parallel circuit: the electric heat generated by each electrical appliance (resistance) in the parallel circuit is inversely proportional to the resistance. Q1/q2 = R2/r1
(3) for the two basic circuit connection methods, it is required to master the painting method of the typical circuit diagram, the connection of the physical circuit diagram, the current characteristics, the voltage characteristics, the equivalent resistance, the electric power characteristics, the electric power characteristics, and the electric heating characteristics.
(4) For an important electrical experiment-voltammetry, we should master the conventional processing methods in the specific experiment of measuring resistance and electric power, including its experimental instruments and experimental principles, circuit Diagram and operation method.