How to learn physical electrical faults? Physical Circuit Issues?

First understand the circuit diagram, and then judge according to the fault.

Distinguish whether it is in series or parallel The ammeter and voltmeter measure which bulb or other electrical appliance is measured.

An increase in the current indication or burnout should cause a short circuit, and an increase in the voltmeter means that the measured electrical appliance is broken, and the resulting indication should be the power supply voltage.

First of all, learn the principle of electrician, and then follow the master to explore in practice.

First learn which conditions will cause what problems, and then the teacher will have special training, that is very simple, as long as you analyze it carefully, you will be right, as long as you are familiar with the circuit diagram, circuit structure, and the connection of each part of the learning is no problem. In a word, listen carefully in class.

First of all, do you mean to do the problem or solve the actual problem?

First, analyze whether it is a short circuit or a short circuit, or because the voltage at both ends of the electrical appliance is too small, the electrical appliance cannot work normally.

After analysis, we are looking at which part of the problem is that the switch is not closed, or the ammeter and the circuit meter are reversed, or other reasons.

Generally speaking, these are the basis for exams.

In addition, if you take the test, if you plug a desk lamp into the socket strip, other electrical appliances will not work, and the plugs and wires will collide.

If it is short-circuited as soon as the switch is turned on, the lines at the lamp head collide.

1. The simplest circuit of the stove belt, no need to add a relay, and the bulb can be connected in parallel with the motor;

2. The control switch needs to be double-controlled, and its current should be greater than the rated current of the motor. If a single-gang switch is to be used, two 24V DC contactors need to be added, and the Nexon circuit is more complex.

3. The two ends of the indicator light require no polarity difference, and the LED indicator light cannot be used. If a DC contactor is installed, an LED indicator can be used.

Poor contact of the voltmeter.

2.The bulb is short-circuited.

3.The light filament broke.

5.The slip rheostat is short-circuited. The bulb is short-circuited.

3 tandem situation.

1.The slip was short-circuited.

Parallel situation. 1.The ammeter is short-circuited.

4.The ammeter was short-circuited.

4..The bulb filament broke.

5.Poor contact of voltmeter2

Example: In a correct circuit, fault judgment is made.

The series circuit 1 voltmeter has no indicator, the ammeter has an indicator, the bulb is bright 2 the voltmeter has no indicator, the ammeter has an indicator, and the bulb is not on.

3. The voltmeter has an indicator, the ammeter has no indication, and the bulb is on.

4. The voltmeter has an indicator, the ammeter has no indicator, and the bulb is not lit.

5. There is a sliding rheostat in the circuit, slide it, and the two representations are unchanged in parallel circuit.

Same as above.

1.Poor contact of the voltmeter.

2.The bulb is short-circuited.

3.The ammeter is short-circuited.

4.The bulb filament broke.

5.The slip was short-circuited.

Parallel situation. 1.Poor contact of the voltmeter.

2.The bulb is short-circuited.

3.The ammeter was short-circuited.

4.The light filament broke.

5.The slip rheostat is short-circuited.

If the current of the ammeter in the circuit is very large and the voltmeter has almost no sight, then the small bulb in the circuit is short-circuited.

If the voltmeter in the circuit is almost equal to the mains voltage, and the ammeter has no sight, then the small bulb is open.

If you move the sliding rheostat, the ammeter and voltmeter do not change much, there are two situations.

1.The bulb is very bright: the sliding rheostat is attached to the upper two binding posts.

2.The bulb is very dim and the sliding rheostat is attached to the lower two binding posts.

<> look at the ways from the positive pole of the power supply to the negative pole, if the resistance of these roads remains unchanged after conversion, it is right.

Middle School Physics: Characteristics of Parallel Circuits.

In junior high school physics, it is common to use ammeter and voltmeter to judge circuit faults, which can be divided into the following situations:

1.The current indication is normal but the voltmeter does not indicate the number:

"Normal current indication number" indicates that the main circuit is the path, and "voltmeter no indication number" indicates that no current passes through the voltmeter, then the cause of the fault may be:

1) The voltmeter is damaged;

2) Poor contact of voltmeter binding post;

3) Short circuit of the electrical appliance connected in parallel with the voltmeter.

2.The voltmeter has an indication and the ammeter does not:

"The voltmeter has an indicator" indicates that there is a current passing through the voltmeter, and "the ammeter has no indicator" indicates that there is no or almost no current flowing through the ammeter, then the cause of the fault may be:

1) Short circuit of ammeter;

2) The electric appliance connected in parallel with the voltmeter is open, and at this time, a large resistance (voltmeter internal resistance) is connected in series in the circuit where the ammeter is located, so that the current is too small, and the ammeter does not display the number clearly.

3.There is no indication of the ammeter and voltmeter

There is no indication in both meters" indicates that there is no current passing through the two meters, in addition to the short circuit of both meters at the same time, the biggest possibility is that the main circuit is open and there is no current.

I hope it helps you, and if you have any questions, you can ask them

I wish you progress in your studies and go to the next level! (*

Junior High School Physical Electrical Faults There are only a few types of junior high school physical electrical faults: short circuits (including short circuits in power supplies and short circuits in local electrical appliances); Opening; The current and voltmeter are reversed and reversed; voltmeter tandem connection and so on. First of all, look at the circuit diagram or physical diagram it gives, and use the current flow direction method (the current starts from the positive pole of the power supply and flows back to the negative through the electrical appliance.

Extreme) to judge the working condition of each electrical appliance. Let's analyze the specific problems in detail.

Some of the important methods that are commonly used are:

The ammeter is seen as a wire, and the voltmeter is seen as an open circuit.

For example: the light does not turn on, the electrical appliances do not work, the possible reasons are:

1) Break the circuit. There is a place in the circuit that is disconnected, including the switch, the appliance itself, poor contact, etc.;

2) Short circuit. The electrical appliance has been short-circuited by a wire or ammeter.

Some issues involving voltmeters:

1) The voltmeter has a reading. However, the ammeter has no reading (or is very weak), the light is not on, and the electrical appliances are not working, the reason: the part connected in parallel with the voltmeter (the voltmeter is used in parallel) is open. In this way, the voltmeter is equivalent to being connected in series in the circuit.

2) There is no reading in the voltmeter. A ammeter has no reading, the light is not on, and the electrical appliance is not working, then, the circuit is broken in parallel with the voltmeter.

b ammeter has reading, and the parallel part of the voltmeter does not work, then, the parallel part of the voltmeter is short-circuited, at this time, the voltmeter is equivalent to parallel with the wire, and the voltage at both ends of the wire is 0

The review of junior high school physics and electricity experiments will be sent to your mailbox, please check.

Circuit Fault Analysis Section.

1. Judgment of circuit breaking.

1. If the electrical appliances in the circuit do not work (often the light is not on), and there is no current in the circuit, the circuit is broken.

2. There are two ways to judge the specific part of the broken circuit:

If the voltmeter is connected in parallel with each place, there is an indication and a relatively large (often expressed as equal to the power supply voltage) at the open circuit (except for the power supply);

Connect the ammeter in parallel with each part separately, and if the other parts can work normally, the part that is connected in parallel with the ammeter at that time is disconnected.

Second, the judgment of short circuit.

1. If some of the electrical appliances in the series circuit or series part cannot work normally, and the other parts of the electrical appliances can work normally, the part that cannot work normally will be short-circuited.

2. The voltmeter is connected in parallel with each part, and the voltage of the wire part is zero to indicate that the wire is normal, if the voltage at both ends of a certain electrical appliance is zero, the electrical appliance is short-circuited.

I am a teacher, and the above is my summary of the types of circuit fault common tests in this year's high school entrance examination, and there are one or two sets of supporting questions, if you don't understand, you can ask me.

Ignore the voltmeter for now.

Then the positive pole of the longitudinal power supply begins to go to the negative pole.

If there is only one pathway, it is a series connection.

If there are n roads, it is parallel.

Let's draw another circuit diagram.

The premise is that there is no fault in the first place.

1 Tandem A table becomes smaller (0 for sure) because the circuit is broken.

A table becomes larger because of a short circuit (i=u r).

If the table A remains unchanged, then no problem.

2.Parallel A meter will not become larger in the trunk circuit (indicating that the resistance has become smaller, which means that the resistance of the branch has become larger.) That's too fake.

Table A is on the branch road, if it remains the same, it means that there is no problem with the electrical appliances along the way with him (if it is short-circuited, it will be burned, this is not considered a change

A table is 0, and the electrical appliances along the way with him are broken, no need to ask.

Table A will not get bigger.

Table no change (1) Measure the total voltage.

2) The electrical appliance he measured was disconnected.

If the V meter becomes larger, it must be connected in series to become larger, indicating that he has an unexpected electrical short-circuit.

The V-gauge has become smaller, and the short circuit he measured has become 0.

Circuit analysis is generally the disassembly of circuits.

Failure analysis should be checked starting with the power supply.

The voltmeter is seen as a large resistance.

The ammeter is treated as a wire.