How to identify NPN tube and PNP tube with HFE file of multimeter
There is a position on the dial of the multimeter marked with the three letters HFE (refer to the picture below). It can be said that this position is specially designed for triodes. In the upper right corner of the dial, we can see that there are 8 jacks. Some numbers and tube types are marked on the surface, so we can use these markings to identify the type of triode being measured.
How to use it? If you don't know anything about this triode at the beginning, you can try to insert the three pins of the triode into the jack. After inserting it, a relatively large and If the number is relatively stable, then we have inserted it right. We can judge according to the information marked on the position where the hole is inserted. We actually took advantage of this in the previous article. Using this method can not only identify the tube In fact, we can also identify the triode pins.
What to do if you find that there is no relatively large number when measuring, it doesn’t matter. We just need to change the inserted hole or change the direction of the triode until it appears as shown in the above two pictures, so that we can identify the tube. The type, even the magnification is also measured, in fact, the magnification is the number displayed on the display screen of the multimeter.
Multimeter to measure the continuity of the circuit
There are circuits and chips in the multimeter. If you want to measure the on-off of the line, you need to adjust the multimeter to the on-off position in the ohm. You can use the red pen and black pen on the meter to measure the on-off. If it is In the connected state, the multimeter will make a beeping sound, and the screen will display a resistance value of 0. If the two ends of the measured line are disconnected, the screen will display the corresponding resistance value or the screen will not change, and there will be no sound, which proves that at this time is in an open circuit state.
Tips, before measuring on-off, you can connect the two ends of the test pen, if there is a sound of beeping, it proves that the on-off gear is normal.
