How To Identify SMD Transistor? And How to Check It? Solved

Transistors are used in many electronic and electrical devices; they have many uses, such as switching and amplifying. Surface mount transistors are one of the types of transistors. The SMD transistors are used mainly in computer boards, so how to identify SMD transistors?

How To Identify SMD Transistor?

To identify an SMD transistor, you have to know the transistor shape; it’s a black-colored rectangular box-like and has pins on its sides. The pins are used for soldering the transistor in computer boards. In addition, you can look up the code labeled on its body and then use the SMD codebook to confirm it’s a transistor.

Unfortunately, some devices may have the same code in the SMD codebook, even if the same manufacturer designed them. Therefore, if you find the code on the transistor body is also used for another component, you can use the shape style of the transistor to differentiate between them.

What Is an SMD Transistor Made of?

Surface mount transistors are made of semiconductor materials, and they are the most component in a transistor. Semiconductor materials only conduct part of the current passing through them; this makes the transistor used as an amplifier or a switch. Amplifiers are usually transistors used to amplify signals.

The electrical signals enter from a certain point in the transistor; they flow to the middle section after passing a barrier; there is a charge subjected to the input at the middle part. After the signals are amplified, they leave the transistor through the third section; the amplifying can be a hundred times the input.

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Can Other Transistors Be Fixed Like SMD Ones?

Yes, other resistors can be fixed to computer boards like surface mount ones; however, the SMD transistors are preferred with computer boards. The bipolar junction transistors are the most popular type of transistors; they have two positive-negative gates which the signals must pass through them.

What Are The Types of Bipolar Junction Transistors?

  • PNP Transistors
  • NPN Transistors

The PNP is positive-negative-positive; meanwhile, the NPN is constructed of negative-positive-negative. The current is amplified after crossing the second gate; it enters the system through the middle part. Another type of surface-mount transistor is the metal oxide semiconductor field-effect transistor.

The MOSFET type is a special type of SMD transistor because it can be either positive or negative. The center probe receives the current from the central area; the central area has the same charge as the output/input port connected to it. The rest of the transistor’s body has the opposite charge.

How To Protect an SMD Transistor?

To protect your SMD transistor, you have to be very careful when fixing it in your computer board because transistors are very delicate, which is not the case for other components. Therefore, you must use the soldering iron very carefully to not damage the transistor. Start soldering metal prongs separately.

Whether they were two or three, each metal prong must be soldered one at a time and leave the piece to rest after each prong is soldered. The transistor’s temperature must decrease to protect it from heat damage.

Source

How To Test an SMD Transistor?

To test an SMD transistor, you will need a multimeter; the multimeter is connected to the transistor to see whether it gives a reading or not; however, testing the transistor is not that simple; you have to follow some certain steps:

Step One

Connect the positive probe from the multimeter to the transistor’s base, and then connect the negative probe from the multimeter to the transistor’s emitter. If your transistor is a good NPN transistor, the reading on the multimeter should be between 0.45 volts and 0.9 volts; meanwhile, for PNP transistors, it’s OL.

Step Two

Connect the negative probe from the multimeter to the transistor’s collector, and then connect the positive probe from the multimeter to the transistor’s base. If your transistor is a good NPN transistor, the reading on the multimeter should be between 0.45 volts and 0.9 volts; meanwhile, for PNP transistors, it’s OL.

Step Three

Connect the positive probe from the multimeter to the transistor’s emitter and then connect the negative probe from the multimeter to the transistor’s base. If your transistor is a good PNP transistor, the reading on the multimeter should be between 0.45 volts and 0.9 volts; meanwhile, for NPN transistors, it’s OL.

Step Four

Connect the negative probe from the multimeter to the transistor’s base, and then connect the positive probe from the multimeter to the transistor’s collector. If your transistor is a good PNP transistor, the reading on the multimeter should be between 0.45 volts and 0.9 volts; meanwhile, for NPN transistors, it’s OL.

Step Five

Connect the positive probe from the multimeter to the transistor’s collector, and then connect the negative probe from the multimeter to the transistor’s emitter. If you have a good transistor, whether an NPN or a PNP, the reading should be OL.

If you reversed the two probes, connect the positive probe from the multimeter to the transistor’s emitter and then connect the negative probe from the multimeter to the transistor’s collector. The reading should also be OL.

What Is an SMD Transistor?

An SMD transistor is a surface mount device and is different from other transistors; it’s soldered directly to computer boards using the pins on its side, lead, and a soldering iron. Although it’s easy to install a surface mount transistor, it can break off easily.

The boards used for SMD transistors are cheaper than normal boards; through-hole transistors are the alternative for surface mount transistors; they are fixed to the computer boards using metal prongs. The boards are designed with holes that the metal prongs can be fitted and drilled through, but they can be costly to manufacture.

Conclusion

To sum up, surface mount transistors are one of the types of transistors; the SMD transistors are used mainly in computer boards, used as an amplifier or as a switch, and used to amplify electrical signals; they can be amplified a hundred times their input. You can identify an SMD resistor using the SMD codebook.

To identify an SMD transistor, you have to know the transistor shape; it’s a black-colored rectangular box-like and has pins on its sides. The pins are used for soldering the transistor in computer boards. In addition, you can look up the code labeled on its body and then use the SMD codebook to confirm it’s a transistor.

However, other resistors can be fixed to computer boards like surface mount ones; however, the SMD transistors are preferred with computer boards. The bipolar junction transistors are the most popular type of transistors; they have two positive-negative gates which the signals must pass through them.

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