There are several different methods of testing transistor using a digital multimeter, however checking the junctions of the transistors is the one that is most frequently used. The emitter, the base, and the collector are the three terminals that are found on a transistor. In order to test the transistor, first need to locate these terminals, which are often indicated on the packaging of the transistor.
Steps involved in Transistor Testing
The following are the steps that need to be taken when using a digital multimeter to test a transistor:
- Make sure that the diode testing mode is selected on your digital multimeter. On the dial of the multimeter, this is often denoted by either a sign for a diode (a triangle that points to a line going vertically) or a symbol for a battery.
- It is necessary to connect the black probe to the emitter terminal of the transistor and the red probe to the base terminal of the transistor. When compared to the emitter, the base of an NPN transistor will have a positive potential. In the circumstance that it is a PNP type, the base will have a negative value in relation to the emitter.
- Take a note of the reading on the display of the multimeter. The reading for an NPN transistor ought to be somewhere in the range of 0.6 to 0.7 volts, whereas the value for a PNP transistor ought to be somewhere in the range of 0.5 to 0.6 volts. If the reading is lower than this, it denotes a short circuit, and if the reading is greater, it shows an open circuit. If the reading is lower than this, it implies a short circuit.
- The next step is to connect the black probe to the collector terminal and the red probe to the base terminal. Do the method as described above, being sure to note the reading on the display of the multimeter.
- Examine the results that were acquired from all three of the exams. If the measurements are within the range that was anticipated, it is probable that the transistor is functioning properly. If the readings are considerably different from one another or fall outside of the normal range, the transistor is probably broken.
It is important to keep in note that the transistor testing procedure given here is simply a basic test, and that it cannot identify all problems. For example, it is unable to identify any intrinsic faults or difficulties that may exist with the gain of the transistor. Yet, it is a fast and simple technique to evaluate whether a transistor is operating properly, which is particularly important in electrical and electronics engineering.