According to the height of the measurement voltage:
High-voltage pencil: Used for 10kv and above project work, for electrician's daily testing equipment;
Low-voltage pencil: For line voltage 500V and the following items of the detection of charged bodies.
Weak pencil: Used for testing electronic products, the general test voltage for 6v--24v. For ease of use, the electroprobe tail often comes with a clip lead.
According to the contact mode:
Contact Tape: The detection Tool for electrical signals is obtained by contacting the charged body. Usually the shape has a screwdriver type, with Tape and a screwdriver; Pen type, display measurement data directly in the LCD window.
Inductive type Tape: Using inductive testing, no physical contact, can check the control line, conductor and socket voltage or along the wire check the circuit breaker position. can guarantee the personal safety of the inspection personnel greatly.
The details are as follows:
A, when pencil to detect a conductor is the line of fire or 0 lines, through the pencil of the current (that is, through the human body of the current) i= added to the pencil and the human body at both ends of the total voltage of U, divided by (/equivalent to the bar) pencil and the total resistance of the
B, when measuring the line of fire, lighting circuit, the line of fire and the ground between the voltage u=220v about, the human body resistance is generally very small, usually only hundreds of to thousands of ohms, and pencil internal resistance is usually a few trillion Europe, through the pencil current (that is, through the human body of the current) is very small, usually less than 1 MA, Such a small current passes through the human body without harming the person, and when such a small current passes through the pencil neon, the neon light glows.
C, when measuring 0 lines, u=0,i=0, that is, no current through the pencil neon, neon bubbles of course does not glow. So we can judge the line of fire or 0 lines according to the neon Light.