NTE159M Transistor : Pin Configuration & Its Applications

The industry standard transistors like NTE123A & NTE159M are used widely in different applications. So the polarity of the NTE123A transistor is NPN whereas NTE159M transistor polarity is PNP. These transistors are available in the TO18 package, so used in audio amplifiers, medium–speed switching, etc. This transistor can be used as a switch or an amplifier.

When the NTE159M transistor is used as an amplifier, it operates in the active region. When it is used as a switch, it operates in both the regions like cut-off and saturation. This article discusses an overview of an NTE159M transistor, pin configuration, features, specifications, and its applications.

What is NTE159M Transistor?

The NTE159M is a PNP type general-purpose transistor and it is available in the TO-18 Package. The complementary NPN type transistor is NTE123A. The maximum gain of NTE159M is 300 & the collector current is 600mA. This collector saturation voltage of this transistor is less like 1V, so applicable in amplifiers & switching-based circuits.

Both the PNP & NPN transistors can form a complementary pair so they can be used where both the PNP & NPN type transistors are necessary like H-bridge circuits, Push-Pull circuits, Class B amplifiers, etc. An alternate package of NTE159M Transistor is 2N2907 transistor which is available in the typical TO-92 package.

NTE159M Transistor
NTE159M Transistor

The NTE159M transistor includes three layers like P, N & P where the ‘N’ layer exists in between two ‘P’ layers. In this transistor, the ‘N’ layer signifies the base (B) terminal and its polarity is negative at the base terminal. P layer signifies the emitter (E) terminal and the polarity at this terminal will be positive (+). To perform, the base terminal of this transistor must be negative as compared to the emitter terminal.

This is a bipolar junction transistor where the conduction will be carried out through both charge carriers like electrons & holes but the majority of charge carriers in this transistor will be holes.

NTE159M Transistor Working:

The working of the PNP transistor is similar to NPN including some exceptions like voltage polarities & direction of current will be opposite in PNP as compared to NPN.


In PNP, the base terminal is negative whereas, in NPN, it is positive. These transistors are called current-controlled devices because, at the base terminal, a small current is used to control the huge current at the remaining terminals.

Once voltage supply is applied at the base terminal of PNP then it is biased, so it allows the charge carriers like holes to supply from emitter terminal to collector. Similarly in NPN, the flow of current will be the same but the majority of charge carriers are electrons.

Pin Configuration:

The pin configuration of the NTE159M transistor includes three pins where each pin and its functionality are given below.

NTE159M Transistor Pin Configuration
NTE159M Transistor Pin Configuration
  • Pin1 (Base): The biasing of the transistor can be controlled through this pin. This pin is used to turn ON/OFF the transistor.
  • Pin2 (Collector): This pin allows the flow of current & normally it is connected to load.
  • Pin3 (Emitter): This pin drains out the current and is connected to the GND terminal.

Features & Specifications:

The features and specifications of the NTE159M transistor include the following.

  • PNP type transistor.
  • Gain of DC or hFE ranges from 100 to 300.
  • Constant collector current or IC is 600mA.
  • Voltage from collector terminal to emitter or VCE is 60 V.
  • Voltage from collector to base terminal or VCB is 60V.
  • Voltage from emitter to base terminal or VBE is 5V.
  • The available package is To-18.
  • Collector current is -0.6 A.
  • Collector dissipation is 0.4 W.
  • The transition frequency is 200 MHz.
  • Operating & storage temperature range is -65 to +200 °C.
  • Common base configuration.
  • 5.84 mm diameter.
  • Dissipation of power is 0.4 W.
  • Dimensions are 5.84 Dia. x 5.33 H.
  • The number of terminals is 3.
  • Height is 5.33mm.
  • The number of Elements for each chip is 1.
  • The material used is ‘Si’.
  • The mounting type is through-hole.

The complementary NTE159M PNP transistor is the NTE123 NPN transistor. The equivalent and replacement of the NTE159M transistor are 2N2907A.

NTE159M transistor’s SMD version is DZT2907A (SOT-223), FMMT2907A (SOT-23), DXT2907A (SOT-89), FMMT2907AR (SOT-23), KN2907AS (SOT-23), FMMTA55 (SOT-23), KST55 (SOT-23), KTN2907AU (SOT-323), KST2907A (SOT-23), MMBTA55 (SOT-23), PMBT2907A (SOT-23), SMBTA55 (SOT-23), FJX2907A (SOT-323), MMST2907A (SOT-323), PZTA55 (SOT-223), KTN2907AS (SOT-23) & PMST2907A (SOT-23).

How to use NTE159M Transistor/Circuit Diagram:

The blown fuse indicator circuit using the NTE159M transistor is shown below. The required electronic components to make this circuit mainly includes NTE159 PNP bipolar transistor (Q1), 1N4148/1N4001 semiconductor diode (D1), red color LED, 510 ohm R1 resistor & 510 K ohm R2 resistor.

The main intention of designing this blown fuse indicator circuit is to give an alert through a RED color LED if there is any problem occurs in electrical systems. So correcting this fault within the electrical systems of a motorcycle or a car is very essential. To overcome this issue first, we need to discover the blown fuse otherwise the problem will increase, so it is very hard to solve this issue.

Blown Fuse Indicator Circuit using NTE159M Transistor
Blown Fuse Indicator Circuit using NTE159M Transistor

In this circuit, the NTE159M PNP transistor is an essential component because it acts as a switch. If the voltage at the base terminal of this transistor is – 0/7V then the fuse working will be good, the PNP transistor moves into the cutoff region so it will not conduct. As a result, the red color LED does not blink.

Similarly, if the fuse in the circuit blows, then there is no flow of current through it. So, the voltage range at the base terminal of the transistor decreases to 0V. At last, this transistor moves into the saturation region which means the flow of current will be there from the emitter terminal to the collector, then the LED will start blinking. So we can conclude that there is an issue within the electrical system.

Basically in an electrical system of the car, there are many types of fuses available. These fuses can be controlled by connecting this blown fuse indicator circuit in parallel through every fuse. So this circuit is used in car radios, toys, battery circuits, etc.

Where to use NTE159M Transistor/Applications:

The applications of the NTE159M transistor include the following.

  • It is used for purpose switching.
  • Amplifiers with high frequency.
  • In designing Class B amplifiers.
  • Switching with medium speed.
  • Push-Pull design circuits.
  • Used in H-bridge circuits.
  • Used in switching circuits.
  • Used in amplifier circuits.
  • These types of transistors can form a complementary pair, used to design a different circuit that uses PNP & NPN like H-bridge circuits, Class B amplifiers, Push-Pull circuits, etc.
  • As a Darlington Pair.
  • Used to make different circuits like dual Led, siren & Lamp flasher.
  • Low power amplification.

Please refer to this link to know more about NTE159M Transistor Datasheet.

Thus, 2N2907 is a PNP-based bipolar junction transistor, used in the applications of low power and switching-based amplification applications. This transistor works at a moderate temperature with high speed. Here is a question for you, what is the difference between PNP & NPN transistors.

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