Use a digital multimeter to determine the transistor pin!

Digital Multimeter is now a very popular electronic measurement tools, because of its ease of use and accuracy by the electronic technology staff's favorite. However, it is often said that when measuring certain components, it is not as convenient as a pointer multimeter, especially when measuring transistors. In fact, I feel a digital multimeter to measure the transistor more convenient.

The inside of the transistor can be seen as a combination of two diodes, as shown in the following figure:

First step: Determine the base and tube type (NPN or PNP)

The above figure shows that the base of the PNP tube is the common denominator of two negative electrodes, the base of the NPN tube is the common denominator of two positive poles. At this point we can use the digital multimeter diode file to test the base pole. For PNP tubes, when the black pen (the negative of the battery in the table) is on the base, the red pen is usually a smaller reading (general 0.5-0.8) with a small difference when measuring the other two poles, such as a larger reading (typically 1) when the pen is reversed. For the NPN tube, the red pen (even the positive battery in the watch) is attached to the base.

Step two: Judge Emitter and collector

If using a pointer multimeter to this step may be used to two hands, and even friends will use the tongue, can be said to be quite troublesome. And the use of the digital table of the three still tube HFE (measuring transistor DC magnification) to be more convenient to test, the multimeter hit the HFE gear, the transistor inserted into the small hole of the NPN, B-pole corresponding to the letter B, reading, and then the other two feet reversed, and then read. The higher the polarity of the reading corresponds to the letters on the table, and the other transistors are the same.