How to use a pencil

Update date:2018-06-06 Source:MAXGE

How to use a pencil

First, the basic usage

The various functions of the pencil cannot be separated from the correct method of use. For the pen, if it is used in the wrong way, there are even dangers of electric shock, so be careful. Here only to talk about the most common, the most inexpensive way to use the test bulb:

1. Clip the insulated part of the pencil between the thumb and middle finger, ring finger and little finger (the thumb on one side and the other three fingers on the other side) and touch the top of the stylus with a metal cap or metal clip.

2. At the other end of the pencil, it is the same thing as a screwdriver. This part can only be in contact with the object being measured. It must not be in contact with the human body.

3. When measuring, hold the electric pen in the above position and touch the measured object with the above-mentioned screwdriver. At the same time, it is necessary to ensure that the body part of the measurer is in contact with the earth (stand directly on the ground, if you wear insulated rubber shoes or stand on the stool, you need to use the other hand to touch the wall).

test pencil

Second, measuring voltage

1, using a stylus to measure the voltage, is the most common method of electric pen. However, it should be noted that the test pencil can only measure the presence or absence of voltage in the circuit and cannot determine the on-off or voltage level of the circuit (the voltage must be the path, but the voltage is not necessarily an open circuit).

2. When measuring, touch the test line with the test pencil. If the test pencil lights up, prove that there is voltage in the line; otherwise, there is no voltage.

3. Before measuring, we must first know the purpose of our measurement. For example, in a single-phase circuit, the FireWire is normally under voltage, and there is no voltage in the neutral and ground wires. Therefore, under normal circumstances, the FireWire can light the electric pen, and the zero ground wire cannot light up. However, when we measure the zero ground wire does not light up the electric pen, it does not mean that the zero ground wire is completely normal and further detection is needed.

Third, distinguish between zero and ground

Differentiating the zero ground has always been a headache for many beginners. But in fact, a pencil can solve this problem. Methods as below:

1. First, use an electric pen to measure several wires in front of them. Only one wire can light up the pen. This line is FireWire.

2. After that, each hand holds a pen, and the measurer stands on the insulating object. Do not touch the earth. One of the electric pens is in contact with the FireWire, and the other electric pen is in contact with the line to be tested. If the two electric pens are not on at this time or the brightness is low, the line to be tested is a ground line. If two electric pens are normally lit at this time, the line to be tested is zero line.

test pencil

Fourth, distinguish AC and DC

Is the line AC or DC? The same electric pen can solve it.

Method 1: There are at least two wires in the circuit, measured by a pen. If one of the two wires can light up the light pen, the rest cannot be lighted, and the circuit is proved to be alternating current. If there are two wires that light up the pen, the circuit is certified as direct current.

Method 2: When the line is AC, the brightness of the pen is high. When the line is DC, the brightness of the pen is low.

Method 3: Observe the lighting position of the electric pen. The same is used to contact the FireWire with the electric pen. If it is a direct current, the helium bubbles inside the Pen will only glow at one end; if it is an alternating current, the helium bubbles of the Pen will light up.

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