How to measure the LED digital tube?
How to measure the LED digital tube?
The appearance discrimination of digital tube usually has 10 pins,usually divided into two rows.When the character is facing up,the pin on the upper left corner is the first foot,and then the other pins are arranged clockwise. Generally speaking,the upper and lower pins are connected to the public pole,and the remaining 8 pins are 7 strokes and 1 decimal points.
Structure and structure type of multimeter foot
The structure of digital tube (common cathode or common anode) is determined.
Put the multimeter in the RX10K2 file and then contact the other pins with a red pen. When the pointer is swinging in a large amplitude (it should indicate a value of about 30K,for example,0 shows red and black pens connected through a common electrode),the black pen connects to the anode,the black pen does not move,and the red pen contacts the other pin in turn.The digital tube S,the needle oscillating,the pen section all luminous,indicates that the black pen does not move.Use the red pen to touch the pins of the nixie tube one by one,the needle does not swing,and the pen does not shine.It is a common cathode.At this time,the rate of dropping pen can be measured,the needle should swing,and all the fragments should shine.
The judgment of good and bad.According to the above measurements,a common electrode is found,and the common anode black pen and the common electrode are sequentially connected to other pins of the digital tube.When the needle is swinging,the pen segments are all luminous,and the common cathode red brush is connected with the common electrode,and the other pins of the digital tube are in contact with the black pen in turn.The needle was all swinging,and all the pieces of the pen glowing.If you touch a PIN, the corresponding pen will not shine and the pointer will not move.This indicates that the section has been damaged.
Determine the arrangement of the pins. With reference to figure,using a multimeter RX10KQ block, the pin parts of the pen are measured respectively,making each part of the pen emitting light points respectively,and can draw out the arrangement of the pins of the digital tube (facing the side of the pen segment) and the interior.RNAL connection.
Detection of all - pen luminescence characteristics
According to the structure and pin configuration of the LED digital tube,check the luminous performance of each section of the digital tube.Take the common cathode as an example,place RX10KQ blocks on the multimeter and connect the red pen to the digital common cathode.the graphic display is the connection diagram of the all optical segment of the digital tube,and the A~P segment of the digital tube is connected together.Then the black pen is exposed to the short end of A~P.At this point,all the pen ends should be lit to show the word "8".The color of luminescence should be uniform, and there is no incomplete or partial discoloration.The public anode test is the opposite.(two batteries can be connected in series,then connected in series,with only a few thousand ohms).
In this experiment,we should pay attention to the following points.
Most LED digital decimal points are not independent,but internally connected to common electrodes.However,the decimal point exists independently in the digital tube.When tandem dry cell method is used for testing,one thousand ohm resistor must be connected in series,otherwise the digital tube will be damaged easily.
When the LED digital tube is damaged,the phenomenon will disappear because of one or several strokes.When the multimeter tests damage the internal luminous tube,the front cover of the digital tube can be carefully opened and the substrate is removed.Figure shows the LED digital tube substrate map.All LED LED is directly fabricated on printed circuit boards on substrates.Use a knife to scrape out the lamp of the damaged section.Install the same color flat light emitting diode in the original position,and pay attention to the polarity of the connection.