Ideas for solving Ohm s law Methods

1: Reasoning according to the formula, as long as you are proficient in the formula and memorize it, it will be easier in the process of solving the problem.

2: It is to seek the solution according to the known conditions given to you by the question, and sometimes, the known conditions given hide other indirect conditions, which gives you clues to the solution.

3: Apply Ohm's law according to the circuit diagram.

4: Use analytical methods.

5: Use the derivation method of columnar equations to solve according to the conversion of equations.

Some circuits apply the Ohm's law formula:

i=u r, u = ri, or i = u r = gu (i=u:r).

Description of the formula. where g = 1 r, the reciprocal g of the resistance r is called conductance, and its SI system is Siemens (s).

i, u, r – the three quantities are the current intensity, voltage, and resistance at the same moment in the same part of the circuit. i q t current charge time (all units are SI units).

That is: current, voltage, resistance.

or Voltage Resistance Current can only be used to calculate voltage and resistance, and does not mean that there is a change relationship between resistance and voltage or current

For series circuits:

i total = i1 = i2 (in a series circuit, the current is equal everywhere).

U total = U1 + U2 (in a series circuit, the total voltage is equal to the sum of the voltages at both ends of each part).

rtotal r1+r2+r3....rn

u1:u2=r1:r2 (series into a positive circle pressure).

p1/p2=r1/r2

When n constant-value resistors r0 are connected in series, the total resistance r=nr0

For parallel circuits:

i total = i1 + i2 (in parallel circuits, the trunk current is equal to the sum of the currents of each branch).

uTotal = u1 = u2 (in parallel circuits, the power supply voltage is equal to the voltage at both ends of each branch).

1 r total = 1 r1 + 1 r2

i1:i2=r2:r1 (parallel inverse flow).

total r = r1·r2 (r1+r2).

r total = r1·r2·r3: (r1·r2+r2·r3+r1·r3).

That is, 1 r total = 1 r1 + 1 r2 + ......1/rn p1/p2=r2/r1

When n constant-value resistors r0 are connected in parallel, the total resistance r=r0 n

That is, the total resistance is less than the resistance of any branch, but the more parallels, the smaller the total resistance.

Series voltage divider (voltage) and parallel shunt (current).

How to say this, you can be specific.

The idea and method of solving Ohm's law is a relationship between voltage and current, r=u i, and knowing two of these three quantities can solve the other quantity.

Hopefully you can be specific, the problem is too big right now to know what to do with you.

First memorize the formula, find the corresponding data when doing the problem, and then use the formula, but some hidden conditions need to be further calculated, first calculate in the exercise book like mathematics, and then think about how to use the formula to find the result.

1. Reasoning according to formulas and being proficient in formulas;

2. It is to pretend to be based on the known conditions given to you by the hail question, and seek to be solved;

3: Apply Ohm's law according to the circuit diagram.

4: Use analytical methods.

5: Use the derivation method of columnar equations to solve according to the conversion of equations.

In the same circuit, the current in the conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to the resistance of the conductor.

When the resistance is constant, the sail current of the electric hall is proportional to the voltage of several widths;

When the voltage is constant, the current is inversely proportional to the resistance. That is, the greater the resistance, the greater the power supply voltage distributed by the resistor itself, and the smaller the voltage at both ends of other appliances.

Answer:1Known: current, voltage. Find the resistance.

2.Known: voltage, resistance. Find the current.

3.Known: resistance, current. Find the voltage.

The computational problem of Ohm's law is one of the difficulties in junior high school electricity. Many students have doubts about the content of solving e-learning problems, especially Ohm's law, and are often helpless and have no idea where to start. So how can we find this "key", open it, close it?

As the saying goes, "If you want to do a good job, you must first sharpen your tools!" "First, we must first grasp the basic content of Ohm's law. Then analyze and judge the circuit, determine the characteristics of the circuit, clarify whether the circuit is a series circuit or a parallel circuit, and then solve the problem according to the relationship between current, voltage and resistance in the corresponding circuit.

The following is a sample solution for reference: the first step. Clarify the essence of Ohm's law.

Ohm's law refers to the fact that in the same circuit, the current in the conductor is proportional to the voltage at both ends of the conductor and inversely proportional to the resistance value of the conductor, which is Ohm's law. The basic formula is bujr. The derivation of Ohm's law u r r=ull or u=lr cannot say that the resistance of a conductor is directly proportional to the voltage at both ends and inversely proportional to the current passing through it, because the resistance of a conductor is a property of the conductor itself, which is related to the length, cross-sectional area, material and temperature of the conductor, even if there is no voltage at both ends and no current passes through it, its resistance value is a fixed value.

The second step is to learn to analyze the circuit. To enter the learning stage of electronics, it is important to be able to "read" circuits.

After memorizing the formula, the value given to the question is brought into the calculation (simple question). If you have a comprehensive question, you should pay attention to the analysis of the circuit diagram, and if the analysis is correct, you can do it correctly.

The reason why it is difficult to solve electrical problems is that there are many formulas and theorems. First of all, you should memorize the current, voltage and resistance rules of series and parallel circuits, but do not memorize them, but pay attention to understanding. For example, "in the parallel circuit, the voltage at both ends of each branch is equal to the total voltage", here it cannot be understood that the voltage at both ends of each electrical appliance is equal to the total voltage in the parallel circuit, otherwise there will be errors when dealing with the problem.

To solve an electrical problem, you must first figure out whether this is a series or parallel circuit, and then choose the corresponding formula. Secondly, you need to know the measurement object of the meter, and finally solve it according to the problem.

When applying the Ohm's law formula, it must be noted that the object of the formula is the same, the circuit is the same time or the same state, and the unit in one is unified.

Learn to look at the diagram, what the voltmeter is connected in parallel with, and what the ammeter is connected in series. Then substitute the formula.

First of all, understand the formulas well, then complete the example problems in the textbook independently, and then do some practice problems to consolidate.

1) What is the resistance of R2?

2) When the switch S is connected to 2, what is the number of the voltmeter? If the power is applied for 1min, what is the heat generated by the resistance r2?

1. The exchange will cause the voltmeter to be connected in series in the circuit, resulting in no current in the whole circuit, and the current representation number is 0, but the voltage representation number is the power supply voltage.

2. The reason is the same as the first question, there must be a voltmeter connected in series into the circuit, but at this time, it is caused by the open circuit of the fixed value resistance.

3. Increase the resistance value of the rheostat, according to the principle of series voltage division, the voltage distributed by the rheostat will increase, and the voltage at both ends of the fixed value resistor will be reduced, so the number of voltage representations at both ends of the fixed value resistor will be reduced in parallel. The ammeter in the circuit decreases as the resistance increases.

(1) The position swap of voltmeter and ammeter can lead to the voltmeter has an indication and the ammeter does not indicate (2) In the process of experiment, it is found that the ammeter has no indication and the voltmeter pointer has obvious deflection, then: The measured resistance is short-circuited (3) If the resistance in the rheostat access circuit is increased, the voltage representation number will become smaller and the current representation will become smaller.

There is no indication of series and parallel mixing.

The voltmeter ammeter is connected to the ** and is not stated.