The relationship between voltage and resistance in series circuits, voltage and resistance in series

Not the resistance is proportional.

Yes, the resistance value is definite. It's like you weigh 120 pounds.

Zhang San is 160 pounds, Xiaohong is 90 pounds, it's not a matter of proportion, so you misunderstand.

Electric current can be thought of as a flow of water, and when passing through a water pipe of the same size, the flow pressure, etc., should be the same.

Voltage becomes voltage in junior high school and electromotive force in high school. Voltage can be understood as water pressure, imagine a stream composed of three waterfalls, is the height difference between the two waterfalls at one end and the other at the end equal to the sum of the height difference between the two waterfalls and the two waterfalls?

The voltage is not proportional to the resistance, and the current is proportional to the voltage. Note that there are only a few reasons why resistance is decided, and you should know about these reasons.

Quite simply, you can imagine connecting all the resistors in a series circuit together without wires. Doesn't that make it a big resistor? In this way, one power supply, one resistor. Of course, there is only one current.

From this point of view, since the current is constant. Let's take this resistor apart again, divide it into several small resistors, and connect them with wires. Then IR1+IR2+IR3+.=i（r1+r2+r3+..=u。

So the voltage is equal to the sum of the voltages at both ends of each resistor.

The most basic problem in a circuit is that you can see both ends of a wire as the same point. This makes it much easier to solve the problem.

According to Ohm's theorem, voltage and resistance are, of course, proportional. The ratio is the current i. This is true even for current changes. It's just a change in the ratio. Still proportional.

The current is the same everywhere in the series circuit, and the premise is that there is no parallel circuit in the circuit. Because the current flows in one wire, it is the same.

In a pure series circuit, the voltage is indeed proportional to the resistance, and the greater the resistance, the greater the voltage applied to it.

In fact, there is a law when it comes to circuits: at the nodes of a circuit, the current flowing in and out is equal. Therefore, in a series circuit, any point can be taken as a node, and the inflow and outflow are equal, so the current is equal everywhere. That's understandable.

When doing electrical problems, first of all, at least one of v, i, and r must be fixed, and ohm's law assumes that the resistance is constant. However, in practice, you can also assume that one of the other two conditions is fixed.

For example, when Ohm's theorem u=IR can push out that voltage is proportional to resistance, and this statement is true, your condition must be that the current is constant. When there is a voltage-current comparison, the resistance must be constant.

The first one doesn't really need to be said, just remember.

No, the resistance you give is a fixed value, and it will not change because you change the voltage or current.

The first one is that if you have to explain, the reason is a bit like the flow of water, if you think about it, the electron is analogous to water.

U=IR,r is the intrinsic property of the resistance does not change with the change of i or u, so it is not a relationship.

As for the first question, I say no. Let's wait for an electromagnetic expert to come to you. It is troublesome to explain and argue.

Resistance is a property of a conductor, and its magnitude is determined by the conductor's cross-section, length, material, and the temperature at which the conductor is subject. However, some students will conclude that when the voltage must be the resistance, it will change with the change of current (the resistance is inversely proportional to the current), and when the current must be the resistance, it will change with the change of voltage (the resistance is proportional to the voltage).

This is false, it can only be said that when the voltage is constant, the current changes with the change in resistance (the current is inversely proportional to the resistance). When the current is constant, the voltage changes with the change of resistance (the voltage is proportional to the resistance).This is also where physics differs from mathematics.

It is important to note that 1 (when the voltage is constant, the resistance is inversely proportional to the current) and 2 (when the voltage is constant, the current is inversely proportional to the resistance) is different. 1 is wrong, 2 is right.

This is found through experiments that the ratio of the amount of charge in the cross-section of a conductor to the time taken is called the current, i=q rate of directional movement of the free charge), q=nq (the amount of charge per free charge) = n (the number of free charges per unit volume and the total number of free charges) = nls (cross-sectional area of the conductor).i.e. i=nqsv

Series circuitsThe currents are equal everywhere.

Expressions：i=i1=i2

2. The total voltage at both ends of the series circuit is equal to the sum of the resistors of each part of the circuit.

Expression: u=u1+u2

3. The total resistance of the series circuit is equal to the sum of the resistance of each part of the circuit.

Expression: companion r=r1+r2

4. Parallel circuit.

The voltage at both ends is equal to the voltage at both ends of each branch.

Expression: u=u1+u2

5. The main circuit current of the parallel circuit is equal to the sum of the currents of each branch.

Tandem, as the name suggests, is a string of connected together; There are more than two resistors, which are connected together in a series one after another to form a circuit without branches, and the sock dismantling of this connection method is a series circuit; When the series is resistor, it is the series resistance. This resistance can be pure resistance, or it can be any component that has a resistance value (such as a load or even the wire itself).

Tandem:

Parallel connection 1, the current is equal; i=i1=i2=…。The total current is equal to the sum of the currents of each branch; i=i1+i2…。2. The total voltage is equal to the sum of the voltages at both ends of each electrical appliance; u=u1+u2+…。

The voltage at both ends of each source is equal; u=u1=u2=…。3. The total resistance is equal to the sum of the resistance of each electrical appliance; r=r1+r2…。The reciprocal of the total resistance is equal to the sum of the reciprocal of the resistance of each branch; 1/r=1/r1+1/r2+…。

Several circuit elements are connected to each other along a single path, with a maximum of two components connected to each node, which is called series connection. Circuits that are connected in series are called series circuits.

The telecommunication currents flowing through each resistor in a series circuit are equal. Because each section of the same branch in a DC circuit has the same current intensity.

The two small bulbs are connected end to end, and then they are connected into the circuit, and we say that the two bulbs are series connection.

A circuit in which an electric current is passed sequentially through each of the constituent elements. The basic feature of a series circuit is that there is only one branch.

In the series circuit, the current is equal everywhere, so it has the effect of dividing the voltage, and the supply voltage is equal to the sum of the voltages of each resistor. Li Min u total = IR + IR . Which race.

In a series circuit, the currents are equal everywhere and the total voltage is equal to the sum of the voltages of the parts.

The total voltage of the series circuit is equal to the sum of the voltages at both ends of each part of the circuit, and its expression is: u total u1 + u2 + u3 + ......ux。

The application of voltmeter in series circuit: the voltmeter is connected in parallel in the series circuit, and it depends on which electrical appliance or power supply is connected to both ends of the positive and negative poles of the meter.

The series circuit has a voltage divider effect. The formula is: u1:u2=r1:r2 (the ratio of resistance in a series circuit is equal to the ratio of voltage).

The sum of the voltages of the parts of the series circuit is equal to the total voltage, the currents are equal, and the total resistance is equal to the sum of the number of resistances at each point.

The sum of the currents of the various branches of the parallel circuit is equal to the total current, and the voltages are equal. In a series circuit, the greater the resistance in the circuit, the greater the voltage distributed by the resistor, and the sum of the voltages at each load is equal to the total voltage. Suppose the total voltage is 10V with two load resistors in the loop.

The resistance values are 1ohum and 9ohm, respectively. In the loop, the total current is 1A, and the current values in the loop are equal everywhere, with a resistance drop of 1 V for 1 ohm and a resistance drop of 9 V for 9 ohm, and the sum of the voltage drops between the two resistors is equal to the total voltage.

What is the difference between series and parallel voltages?

Series circuit: The current in all series elements is the same current, i total = l1 = l2 = l3 = ·· ln。 The total voltage of the components in series is the sum of the terminal voltages of all the components, u total = u1 + u2 + u3 + ......un。

Parallel circuit: the terminal voltage of all parallel components is the same voltage, u total = u1 = u2 = u3 = ·· un。 The total current is the sum of the currents of all components, i total = i1 + i2 + i3 + · · in。

Series circuits are characterized by the fact that current flowing through one component also flows through another. For example:

A small lantern at the festival. In the series circuit, the switch is closed, the two bulbs emit light at the same time, and the two bulbs are off when the switch is disconnected, indicating that the switch in the series circuit can control all the electrical appliances. Parallel circuits:

A circuit consisting of components connected side by side is characterized by the fact that the current from the trunk circuit is divided into two parts and flows through each element in the two branches. For example:

Connections of various electrical appliances in the home. In the parallel circuit, the switch on the trunk road is closed, the switch on the branch road is closed, the bulb will shine, the switch on the trunk road is disconnected, the switch on each branch road is closed, and the bulb will not emit light, indicating that the switch on the trunk road can control the entire circuit, and the switch on the branch road can only control the branch.

1. The characteristics of the series circuit (U represents the voltage, I represents the current, and R represents the resistance) 1. The current in the series circuit is equal everywhere.

i=i1=i2=i3=……in

2. The total voltage in the series circuit is equal to the sum of the voltages of each part of the circuit.

u=u1+u2+u3+……un

3. The total resistance in the series circuit is equal to the sum of the resistance of each part of the circuit.

r=r1+r2+r3+……rn

4. The voltage at both ends of each part of the circuit in the series circuit is proportional to its resistance.

u1/u2=r1/r2 u1:u2:u3:…=r1:r2:r3:…Second, the characteristics of parallel circuits:

1. The total current in the parallel circuit is equal to the sum of the currents in each branch.

i=i1+i2+i3+……in

2. The voltages at both ends of each branch in the parallel circuit are equal.

u=u1=u2=u3=……un

3. The reciprocal of the total resistance of the parallel circuit is equal to the sum of the reciprocal resistance of each branch.

1/r=1/r1+1/r2+1/r3+……1 RN4, in a parallel circuit, the current flowing through each branch is inversely proportional to its resistance.

i1/i2= r2/r1

in series circuits.

1. The working characteristics of electrical appliances: the electrical appliances affect each other, and if one electrical appliance in the circuit does not work, the rest of the electrical appliances will not work.

2. Switch control characteristics: the switch in the series circuit controls the whole circuit, and the switch position changes, which has no impact on the control function of the circuit. That is, the control role of the switch in a series circuit has nothing to do with its position in the circuit.

Series circuit, voltage two main features:

The total voltage is equal to the sum of the voltages at both ends of each resistor.

i.e. u=u1+u2+......rn。

The voltage at each end of the resistor is proportional to their resistance.

i.e. u1:u2:......un=r1：r2：……rn。

Characteristics of series circuits.

1. The current is equal everywhere in the series circuit.

2. The total voltage in the series circuit is equal to the sum of the voltages of each part of the circuit.

3. The total resistance in the series circuit is equal to the sum of the resistance of each part of the circuit.

4. The voltage at both ends of each part of the circuit in the series circuit is proportional to its resistance.

The current flow method is usually used to determine the connection of a circuit. If the current passes through each consumer in sequence without shunting, the consumer is connected in series; If the current through the consumer is bifurcated, i.e., the current passing through each consumer is part of the total current, then the electricity is connected in parallel. When judging the connection of a circuit, it is usually possible to use a wire to connect two points of the circuit, and in the junior high school stage, the resistance of the wire can be ignored, so it is possible to see the two points connected by a wire as a point, so sometimes it is convenient to use the "node" method to judge the connection of the circuit.

The series connection of resistors has the following characteristics: (refers to R1, R2 series series, the more strings, the greater the resistance) Current: i=i1=i2 (the current is equal everywhere in the series circuit) Voltage: u=u1

u2 (the total voltage is equal to the sum of the voltages everywhere).

Resistance: r=r1

r2 (total resistance is equal to the sum of each resistance) If n equivalent resistors are connected in series, then there is r total = nr voltage divider: =; Calculate u1, u2, available:;

Proportional relationship: current: i1:i2=1:1

The parallel connection of resistors has the following characteristics: (refers to R1, R2 in parallel, and the more they are combined, the smaller the resistance) Current: i=i1

i2 (the trunk current is equal to the sum of the currents of each branch).

Voltage: U=U1=U2 (Trunk voltage is equal to the voltage of each branch) Resistance: (The reciprocal of the total resistance is equal to the reciprocal sum of each resistor) If n equivalent resistors are connected in parallel, then there is r total = r

Diversion effect:; Compute i1, i2 available:;

Proportional relationship: voltage: u1:u2=1:1