What Is a Transistor Checker?

Transistor checkers, also known as transistor testers, are devices used to test the electrical behavior of transistors and diode states within transistors. The transistor device is commonly used for circuitry and electronics. Most transistor checkers test whether or not a transistor is sinking input (NPN) or sourcing output (PNP). There are also different types of transistors, depending on what the device is testing.

An automatic transistor checker is used to test bipolar junction transistors. It uses a method to type, pin and check for forward direct current (DC) gain. The automatic transistor checker is most often used on small, portable electronic devices because it uses little battery power to measure the forward DC gain. This type of transistor checker automatically determines whether the transistor type is NPN or PNP, as well as a pinout. The device is also useful for quick-checking batches in unknown devices.

Circuit transistor checkers test any kind of transistor that is connected to circuitry in electronic devices. Transistors are often soldered onto a circuit board, which makes it difficult to determine if a problem on the circuit board arises from a transistor or something else. Unsoldering transistors is not practical, so a circuit transistor checker can check the transistor without the need to remove it. This type of circuit transistor checker tests the transistor by calculating the wavelength of the transistor signal that appears over the load hindrance of a test set. It also measures DC flow at certain points in a test circuit.

Another type of transistor checker is the SCR, Diode and Transistor Analyzer. This type of checker tests various electronic components, including silicon-controlled rectifiers or semiconductor-controlled rectifiers (SCRs); diodes, which are semiconductor devices that pass electrical currents in only one direction; and transistors. The checker performs a few tests on each component, including opens, shorts, and standard operating condition. For transistors, it will test the audio oscillator function. Testing involves connecting the SCR, diode or transistor to the checker.

Thin film transistor (TFT) checkers test the thin film transistor’s electrical characteristics. The TFT checker tests this kind of transistor through a non-contacting current source, protecting the TFT from unfavorable effects like contamination and destruction. A transistor checker tests the array substrate of a TFT, including supply devices of ion flow and ion flow on the substrate surface. This kind of checker is beneficial because it does not have to connect to a transistor to properly work.