The Function and Correct Usage of a Test Pen
The correct use of digital display test pens should master the following contents:
(1) Button Description:
(A key) DIRECT, directly measure the button (far from the LCD screen), that is, when using the pen to directly contact the circuit, please press this button.
(B key) INDUCTANCE, induction measurement button (close to the LCD screen), that is, when using the pen to sense contact with the circuit, please press this button.
Note: No matter how the pen is printed, please remember that the one far away from the LCD screen is for direct measurement; The one closest to the liquid crystal is the sensing key.
(2) The digital display test pen is suitable for direct detection of AC and DC currents ranging from 12 to 250 V, as well as indirect detection of AC zero lines, phase lines, and breakpoints. It can also measure the on/off of uncharged conductors.
(3) Direct detection:
① The last number is the measured voltage value.
② When the high break display value is not 70%, the low break value is displayed.
③ When measuring direct current, touch the other pole with your hand.
(4) Indirect detection: Hold down the B key and place the pen tip close to the power cord. If the power cord is live, the high voltage symbol will be displayed on the display of the digital display pen.
(5) Breakpoint detection: Press and hold the B key, and when moving longitudinally along the wire, the breakpoint is located where there is no display in the display window.
Alternative usage methods for measuring electric pens
(1) It can be used for low-voltage nuclear phase measurement to determine whether any wires in the circuit are in phase or out of phase. The specific method is to stand on an object that is insulated from the ground, hold a measuring pen with both hands, and then test on the two wires to be tested. If the two measuring pens emit very bright light, the two wires are out of phase; On the contrary, it is in phase, which is judged based on the principle that the voltage difference between the two electrodes of the neon bubble in the measuring pen is directly proportional to its luminous intensity.
(2) It can be used to distinguish between alternating current and direct current. When using a test pen for testing, if both poles in the neon bubble of the test pen emit light, it is an alternating current; If only one of the two poles emits light, it is direct current.
(3) It can determine the positive and negative terminals of direct current. Connect the test pen to a DC circuit for testing, and the electrode with the neon bubble shining is the negative electrode, while the electrode without the neon bubble shining is the positive electrode.
(4) It can be used to determine whether the DC is grounded. In a DC system with insulation to ground, standing on the ground can be used to contact the positive or negative poles of the DC system with a measuring pen. If the neon bubble of the measuring pen is not lit, there is no grounding phenomenon. If the neon bubble lights up, it indicates grounding. If it lights up at the tip of the pen, it indicates positive grounding. If it shines on the finger end, it is negative grounding. However, it must be pointed out that in DC systems with grounding monitoring relays, this method cannot be used to determine whether the DC system is grounded
