The non-contact dc voltage tester pen detector is also called the test pen.It is an electrical tool used to test whether a wire is charged.There is a neon bubble in the pen body. If the neon bubble glows during the test, it indicates that the wire has electricity or is the fire line of the path.In the test pen, the pen tip, the pen tail, is made of metal material, the pen rod is made of insulation material.When using test pencil, must use hand to touch the metal part of the end of a test pencil, otherwise, because of the charged body, test pencil, the human body with the earth did not form a loop, neon bulb does not shine in the test pencil, wrong result, don't think a charged body is charged.
Type of non contact voltage tester pen
According to the high and low voltage measured:
High voltage measuring pen: it is used for 10kv or above project operation, and it is the daily testing equipment for electricians.
Low voltage measuring pen: used for the detection of charged body of line voltage 500V and below.
Weak current measuring pen: used for testing electronic products, the test voltage is generally 6v--24v. For convenience of use, the end of the electric pen is usually equipped with a lead wire with a clamp.
According to contact mode:
Contact stylus: a tool for detecting electrical signals by touching a charged body.Usually in the shape of a word screwdriver, both for a test pen and a word screwdriver;Pen type, display measurement data directly in the liquid crystal window.
Inductive test pen: use inductive test, no physical contact, check the voltage on the control line, conductor and socket or check the position of break along the wire.It can greatly guarantee the personal safety of inspectors.
Specific instructions are as follows:
A, when the test pencil to detect A conductor wire or zero line, by combination of current (that is, through the body's current) I = on test pencil and human body on both ends of the total voltage U, divided by (/ fractional line) test pencil and total resistance R at the ends of the human body.
B, when measuring wire, lighting circuit, voltage between wire and to be around U = 220 v, the body resistance is generally small, usually only a few hundred to several thousand ohms, and internal resistance test pencil is usually around a few ohms, by combination of current (that is, through the body's current) is very small, usually less than 1 ma, in such a small current through the body, no harm to people, and in such a small current through the neon bulb test pencil, neon bulb glows.
C. When measuring the zero line, U=0, I=0, that is, the neon bubble with no current passing through the measuring pen, of course, the neon bubble does not glow.So we can tell if the neon is emitting light or if it's zero.
Use of non-contact ac voltage pen detector tester meter
Besides judging whether an object is electrically charged, there are several USES of the instrument
(1) it can be used to carry out low-voltage nuclear phase, and measure whether any wires in the line have the same phase or different phase.Specific method is: standing on an object with the earth insulation, hands each hold a test pencil, and then in the two wires under test to test, if the two test pencil light is very bright, the two wire as heterogeneous;Otherwise, it is the same phase, which is determined by the principle that the voltage difference between the neon poles in the measuring pen is proportional to its luminous intensity.
(2) it can be used to distinguish alternating current from direct current.When tested with a stylus, alternating current occurs when two of the electrodes in the neon bubble glow.If only one of the two poles emits light, it is direct current.
(3) the positive and negative poles of dc can be determined.Connect the measuring pen to the dc circuit and test it. The one that neon lights is negative, and the one that doesn't is positive.
(4) it can be used to determine whether dc is grounded.In a ground-to-ground insulated dc system, you can stand on the ground and touch the positive or negative poles of the dc system with a measuring pen.If neon lights up, it's grounded. If it's on the tip of a pen, it's grounded.If it is shiny on the finger end, it is grounded to the negative pole.However, it must be pointed out that in a dc system with a ground monitoring relay, this method cannot be used to determine whether the dc system is grounded.
A measuring pen is one of the tools used by many electricians to determine whether an object is charged.The inner structure is a bulb with only two electrodes, and the bulb is filled with neon gas, known as a neon bubble. One end is connected to the pen tip, and the other end is connected to the other end of the pen with high resistance.When the voltage between the neon poles reaches a certain value, a glow is generated between them, and the glow is proportional to the voltage between them.When the charge is applied to the earth at a voltage greater than the glow voltage at the beginning of a neon bubble, it glows when the tip of the pen is touched to it and the other end is grounded by the human body.The function of resistance in a measuring pen is to limit the current flowing through the body to avoid danger.