Junior high school physical circuit judgment fault 5

Actually, it's not a contradiction.

Let's take the diagram as an example. If the B circuit is broken, then the A circuit is still the path, and the voltmeter has an indication and is the supply voltage. This statement is not contradictory when such a voltmeter is connected in parallel with the open part.

There is no contradiction, this depends on the situation, the power supply provides the voltage, so the voltmeter has an indication, it is certain that the two binding posts from the voltmeter to the power supply are the path, and there is no reading if the voltmeter is not available.

However, there may be an open circuit in the part of the circuit connected in parallel with the voltmeter, because as long as the voltmeter is connected to the power supply 2 sides, there will be readings, so the parallel part does not affect the reading of the voltmeter.

Your second paragraph is judging the circuit, not like a series circuit, the voltmeter is the power supply voltage, which means that the parallel part is open.

These two views are not contradictory, on the contrary, one point of view can be used to prove that the other is correct. If the voltmeter is measured by the circuit open, then the voltmeter measures the power supply voltage, which means the external voltage in addition to the measurement circuit, at this time, if the voltmeter has an indication, it can be said that the circuit at both ends of the voltmeter is intact, that is to say, the voltmeter two binding posts to the power supply two levels for the path, if you still do not understand, you can continue to ask!

This is for different circuit diagrams, the first one is the premise that there is a zero ammeter! And the voltmeter has an indication! Otherwise it can't be said otherwise!

And the second one is a voltmeter to measure one. There is also a circuit element that is measured in series with the voltmeter. That's it!

The premise of the two is different, and you can't use the same language! You shouldn't hold on to certain languages! Isn't there some way to judge?

Four Ways to Simplify Your Circuit! One: The ammeter switch is equivalent to a wire.

2: It can be directly erased if it is connected in parallel with the wire. Three:

The disconnection can be wiped off directly to the intersection of the line. Four: the voltmeter can be directly erased.

In a parallel circuit, the voltages are equal everywhere, while in a series circuit, the total voltage is equal to the sum of the partial voltages, (Isn't the voltmeter connected in parallel at both ends of the appliance?). The two ends of the voltmeter are connected to the power supply, right? Originally, how could the voltmeter have voltage when there was no voltage?

Therefore, it is certain that the two terminals of the voltmeter to the power supply are the path, if there is only one electrical appliance, then the voltmeter measures the voltage of the electrical appliance, that is, the power supply voltage. In the electrical appliances with two or more voltmeters measure the voltage at both ends of the binding post, it may be a small section of the circuit, so when the voltage is expressed as the power supply voltage, the other part of the circuit measured by the voltmeter is open, depending on the problem, the circuit is actually a seemingly complex but not complicated thing, you can learn well by doing more questions, I believe you can learn very well!

The voltmeter has an indication of the following conditions: 1. The circuit is normal, and the resistance of the measured part is not zero; 2. The circuit under test is broken, and the indication is the power supply voltage.

There is no indication of the voltmeter, and there are some columns: 1. The circuit is normal, and the resistance of the measured part is zero; 2. The power supply from one side of one of the binding posts of the voltmeter to the power supply part is broken.

The voltmeter is to measure the power supply side, for example, if your home trips, the voltage at home must be no longer measured by the voltmeter, but you measure the voltage of the upper power supply, so the load side is short-circuited, just to say that this is not a complete circuit without current through the load, but the voltage at the power supply side still exists, the above sentence for the path refers to the voltmeter to the power supply for the path, the next sentence is to say that there is a short circuit at the back end of the voltmeter, there is no logic problem.

There are two main types of faults: open circuit and short circuit.

If the component is disconnected, its current is 0 and there may be voltage at both ends;

If the component is short-circuited, the voltage across it is 0 and there may be current flowing through it.

It's simple, so it's a hindrance.

1. The power supply heating will inevitably cause a short circuit in the power supply of the wheelman.

2. If a part of the electrical appliance in the series circuit cannot work, then this part must have a short circuit.

3. Most of the faults in the parallel circuit can be analyzed directly by using the characteristics of the parallel circuit.

Methods for detecting other circuit faults:

1. Connect the intact electrical appliances in parallel with the circuit under test. (for short-circuit faults in series circuits) 1. The electrical appliances work normally. Description: An open circuit occurred on the circuit under test.

2. Electrical appliances cannot work. Description: An open circuit occurred on an untested circuit. Resistant sail.

2. Use the wire to connect in parallel with the circuit under test. (for series circuits) 1. The untested circuit works normally. Description: An open circuit occurred on the circuit under test.

2. The untested circuit cannot work. Description: An open circuit occurred on an untested circuit.

In the category of junior high school physics failures, there are three kinds of faults, power short-circuit, local short-circuit, and open circuit.

To determine whether it is a short circuit or an open circuit, the key is whether there is a current, and to observe the light emitting of the bulb or the number of current indications.

There is a current in a local short circuit, and if there is a short circuit in the power supply, the current is too large, and there is no current in the open circuit.

Judge the location of the open circuit, connect a wire in parallel at the place where the open circuit may be broken, and if the open circuit is there, the current will be restored to the other side of the bench bend of the circuit.

To judge the short circuit, connect the upper voltmeter in parallel at the place where the short circuit may be, if there is no indication, the jujube mold indicates that the short circuit is there.

The method of judging a circuit fault is as follows:

1.Judge short circuit or open circuit through the ammeter, if the ammeter has an indication, it will be short-circuited; If the ammeter does not indicate the number, the circuit will be opened.

2.Then through the voltmeter ammeter situation, determine which electrical appliance fault is the fault, when the voltmeter and the ammeter have an indication and one has no indication, You Hui will be the electrical fault measured by the voltmeter; When both the voltmeter and the ammeter have no indication or both have an indicator, the other non-voltmeter is faulty.

The method of judging the open circuit and short circuit is as follows:

Judgment of open circuit.

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 open.

2. There are two ways to judge the specific part of the open road:

If the voltmeter is connected in parallel with each place, there is an indication and it is relatively large (often expressed as equal to the power supply voltage).

then the circuit between the two binding posts of the voltmeter is open (except for the power supply).

If the other parts can work normally and the ammeter has current, the part that is connected in parallel with the ammeter at that time is disconnected. (Applicable to series circuits of multi-purpose electrical appliances).

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 respectively, and the voltage of the wire part is zero, which means that the wire is normal, if the voltage at both ends of a certain electrical appliance is zero, the electrical appliance is short-circuited.