Ohm s law for closed circuits, Ohm s law for closed circuits

1) A simple and rough measurement voltmeter is connected directly to the reading between the two poles of the power supply.

2) A more accurate measurement is to connect an ammeter in series in the circuit, connect different resistors R1 and R2 twice, and read the readings I1 and I2 respectively.

e=i1r1+i1r

e=i2r2+i2r

The values of e and r can be solved.

3) The most accurate measurement is similar to voltammetry resistance measurement, the power supply is connected to a sliding rheostat, the voltage meter at both ends of the rheostat is connected in parallel, the series ammeter in the circuit, the value of the sliding rheostat is changed many times to several groups of voltage values and current values, the coordinate system is established, the vertical axis represents the voltage U, the horizontal axis represents the current value I, the point is drawn, the line is drawn (let the vast majority of points concentrate on **, and the individual deviation is caused by accidental error, and the intercept between this line and the vertical axis is e, and the intercept of the transverse axis is i = e r, and r can be obtained.

The current of the closed circuit is directly proportional to the electric compass potential of the power supply, and inversely proportional to the sum of the resistance of the internal and external circuits.

The formula is i=e (r+r), i represents the current in the circuit, e represents the electromotive force, r represents the total external resistance, and r represents the internal resistance of the battery. Commonly used variants are e=i (r+r); e=u-outside + u-inside; U Outer = E IR

The law states that the current in a closed circuit depends on the two types of finger sock factors, i.e., the electromotive force of the power supply and the total resistance of the closed circuit, which is the unity of a pair of contradictions in the circuit. The variant e=uout+uin=i (r+r) shows that the potential rise and fall are equal in a closed circuit. The current in the closed circuit is directly proportional to the electromotive force of the power supply and inversely proportional to the resistance of the entire electrical circuit.

The current of the closed circuit is directly proportional to the electromotive force of the power supply, and inversely proportional to the sum of the resistances of the internal and external circuits.

1. The energy conversion relationship in the closed loop.

If the electrical power of the external circuit is a pure resistance circuit, the energy conversion relationship of the external circuit is the conversion of electrical energy into heat energy. E outside = i rt = q heat.

The internal circuit also has the internal resistance of the power supply r, and when the current i flows through the power supply, there is also a part of the electrical energy converted into heat energy. E within = i rt = q heat.

The energy in the circuit is derived from the work done by the non-electrostatic force inside the power supply: w=eq=eit.

By the law of conservation of energy: w = e outside + e inside.

That is: eit=i rt+i rt e=ir+ir=i(r+r) i=e (r+r) (closed electric filial piety years old road ohm's law expression).

2. Ohm's law for closed circuits.

1. Expression: The current in the closed circuit is proportional to the electromotive force of the power supply, and inversely proportional to the sum of the resistance of the internal and external circuits.

2. Expression: i=e (r+r).

3. Description: 1) i=e (r+r) is only applicable to pure resistive circuits.

2) U outside = IR is the electric potential on the external circuit to attack and land, U outside is customarily called the road-end voltage.

3) U = IR is the potential drop on the internal circuit, which is customarily called the internal voltage.

4) by i=e (r+r) e=ir+ir=uouter + u-inside.

The power distribution relationship on the closed circuit reflects the conversion and conservation of energy in the closed circuit, part of which is consumed on the internal resistance, and the rest is output to the external circuit, and converted into other forms of energy in the outer circuit.

When the current in the circuit is maximum, the power dissipated on the constant-value resistor is maximum. When it is a sliding rheostat, the analysis depends on the specific situation, and the resistance outside the sliding rheostat can be regarded as the internal resistance of the power supply in combination with the relationship between the maximum power output of the power supply, and the circuit can be equivalent to a new circuit composed of a new power supply and a sliding rheostat, and then the relationship between the maximum power output of the power supply can be analyzed.

From the point of view of energy conversion, two forms of energy conversion are carried out simultaneously in a closed circuit: one is to convert other forms of energy into electrical energy, and the other is to convert electrical energy into other forms of energy. Let a positive senile charge q, starting from the positive electrode and rotating through the outer circuit and the inner circuit, then the energy conversion situation on the inner and outer circuits.

In an external circuit, the positive charge Q overcomes the obstacle of the external resistance under the action of the electric field force and moves from the positive electrode to the negative electrode, in which the electric field force pushes the charge to do work. If the terminal voltage of the external circuit is U, then in the process of the positive charge being transferred from the positive electrode to the negative electrode through the external circuit, the work done by the electric field force is W = qu, so there must be an electrical energy with a value of qu converted into other forms of energy.

Ohm's law for closed circuits is i=e (r+r), where i represents the current, e represents the electromotive force, r represents the total external resistance, and r represents the internal resistance of the battery. Ohm's law for closed circuits is i=e (r+r), where i is the current, e is the electromotive force, r is the total external resistance, r is the internal resistance of the battery, and the current is related to the power supply. The electromotive force is proportional, and the sum of the electric and internal and external circuits is inversely proportional.

The current of the closed circuit is directly proportional to the electromotive force of the power supply, and inversely proportional to the sum of the resistances of the internal and external circuits. The formula is i=e (r+r), i represents the current in the circuit, e represents the electromotive force, r represents the total external resistance, and r represents the internal resistance of the battery.

Ohm's Law Meaning Explained

The law says that Lu Zhengming states that the current in a closed circuit depends on two factors, namely the electromotive force of the power supply and the total resistance of the closed circuit, which is the unity of a pair of contradictions in the circuit. The variant e=uout+uin=i (r+r) shows that the potential rise and fall are equal in a closed circuit.

The voltage measured between the two poles of the power supply with a voltmeter is the road-end voltage U, not the voltage U at both ends of the inner circuit, nor the electromotive force of the power supply, so when the power supply is not connected to the circuit, because there is no current through the internal circuit, so U = 0, at this time E = U outside, that is, the power supply electromotive force is equal to the road-end voltage when the power supply is not connected to the circuit.

E=i, (r+r) is only applicable to closed circuits where the external circuit is pure resistor. U Outside = E IR and E = U Outside + U inside are available for all closed circuits.

How to distinguish between closed and partial circuits

Distinguish. Ohm's law for closed circuits clarifies the relationship between the electromotive force of the power supply, the voltage at the end of the road, and the voltage within the power supply in the whole circuit, including the power supply.

Mathematical expression: e=uoutside+uinternal, suitable for all circuits.

Ohm's law for partial circuits only indicates the relationship between current, voltage, and resistance of partial circuits.

Mathematical expression: i=u r

Contact. i=e (r+r), i=u r is suitable for pure resistive circuits; Ohm's law for closed circuits contains some of Ohm's laws for circuits.

Ohm's law for closed circuits (for a macro-chaotic given power supply: it is generally believed that e,r does not change, but after a long period of battery use, e becomes slightly smaller and r increases significantly).

Ohm's Law Applies Condition:

1. In the case of normal temperature or temperature is not too low, Ohm's law is a very accurate law for conductor cavities (such as metals) where electrons conduct electricity. When the temperature is low to a certain temperature, the metal conductor may move from the normal state to the superconducting state. The resistance of a conductor in a superconducting state disappears, and there can be a current without adding voltage.

Ohm's law certainly no longer applies in this case.

2. Ohm's law also applies to ionically conductive conductors such as electrolytes (aqueous solutions of acids, alkalis, and salts) when the temperature or temperature change range is not too large. Ohm's law does not hold true for the conductive state presented under the condition of gas ionization, and for some conductive devices, such as electron tubes and transistors.

3. When Ohm's law is established, the curve made by taking the voltage at both ends of the conductor as the abscissa and the current i in the conductor as the ordinate is called the volt-ampere characteristic curve. This is a straight line through the origin of the coordinates, and its slope is the reciprocal of the resistance. Electrical components with this property are called linear elements, and their resistance is called linear resistance or ohmic resistance.

4. When Ohm's law is not true, the volt-ampere characteristic curve is not a straight line passing the origin, but a curve of different shapes. Electrical components with this property are called nonlinear components.