Transistor Functions and How to Measure it

Transistor Function and How to Measure It – Transistor is one of the most commonly used Active Electronics Components in Electronics circuits, both the simplest electronic circuits and complex electronic circuits. Transistors are generally made of semiconductor materials such as Germanium, Silicon, and Gallium Arsenide. In general, transistors can be divided into 2 types, namely bipolar transistors (BJT) and field effect transistors (FET).

Read also Definition of Transistors and Types of Transistors

Transistor Function

Transistor functions include:

• As a recesser,
• as a voltage and power amplifier,
• as a voltage stabilization,
• as a mixer,
• as an oscillator
• as Switch (Circuit Breaker and Connector)

Basic Structure of Transistors

Basically, Transistor is an Electronic Component consisting of 3 Semiconductor Layers and has 3 Terminals (legs) namely the Emitor Terminal abbreviated with the letter “E”, Terminal Base (Base) abbreviated with the letter “B” and Terminal Collector / Collector abbreviated with the letter “C”. Based on its structure, transistors are actually a combination of two diode joints. From the combination, transistors are then divided into 2 types, namely NPN type transistors and PNP type transistors also called bipolar transistors. Bipolar is said to have two polarities in carrying an electric current.

NPN stands for  Negative-Positive-Negative  while  PNP  stands for  Positive-Negative-Positive.

The following is an image of the transistor type based on the semiconductor layer that makes it up along with the transistor symbols NPN and PNP.

How to Measure Transistors

We can use analog multimeters or digital multimeters to measure or test whether a transistor is still in good condition. It should be noted that there are differences in polarity layout (Red and Black) Analog Multimeter Probe and Digital Multimeter in measuring / testing a Transistor.

Here is how to test or measure transistors using analog multimeters and digital multimeters.

• Measuring Transistors with Analog Multimeters

How to Measure PNP Transistors with Analog Multimeters

1. Set the Switch Position at OHM (Ω) x1k or x10k position
2. Connect the Red Probe on the Base Terminal (B) and the Black Probe to the Emitter Terminal (E), If the needle moves to the right showing a certain value, it means that the transistor is in good condition.
3. Move the Black Probe to the Collector Terminal (C), if the needle moves to the right showing a certain value, it means that the transistor is in good condition.

How to Measure NPN Transistors with Analog Multimeters

1. Set the Switch Position at OHM (Ω) x1k or x10k position
2. Connect the Black Probe on The Base Terminal (B) and the Red Probe to the Emitter Terminal (E), If the needle moves to the right showing a certain value, it means that the Transistor is in good condition
3. Move the Red Probe to the Collector Terminal (C), if the needle moves to the right showing a certain value, it means that the transistor is in good condition.

Note:
If the Probe Layout is reversed from the above-mentioned method, then the Needle on the Analog Multimeter must not move at all or “Open”.

 

• Measuring Transistors with Digital Multimeters

In general, Digital Multimeters have the function of measuring Diode and Resistance (Ohm) in the same switch. So for this type of Digital Multimeter, Multimeter Testing is inverted by Testing Transistors Using Analog Multimeters.

How to Measure PNP Transistors with Digital Multimeters

1. Set the Switch Position on the Diode Position
2. Connect The Black Probe on The Base Terminal (B) and the Red Probe to the Emitter Terminal (E), If the Multimeter Display shows a certain Voltage value, it means that the Transistor is in good condition
3. Move the Red Probe to the Collector Terminal (C), if the Display Multimeter is of a certain Voltage value, meaning the Transistor is in good condition.

How to Measure NPN Transistors with Digital Multimeters

1. Set the Switch Position on the Diode Position
2. Connect the Red Probe on the Base Terminal (B) and the Black Probe to the Emitter Terminal (E), If the Multimeter Display shows a certain Voltage value, it means that the Transistor is in good condition
3. Move the Black Probe to the Collector Terminal (C), if the Multimeter Display shows a certain Voltage value, it means that the Transistor is in good condition.

Note:
If the Probe Layout is reversed from the above-mentioned method, then the Digital Multimeter Display should not show voltage or “open” values.