Blog  /  MPSA18 Pinout: Complete Guide on How to Use It

MPSA18 Pinout: Complete Guide on How to Use It

MPSA18 pinout is in the category of the NPN general-purpose transistor types.

Importantly, this NPN transistor is among the high-gain transistors with low noise.

You will mostly find the MPSA18 transistor in low-power audio amplifier circuits.

The transistor can build a low-noise amplifier(LNA). The LNA works by preventing amplified noise.

Therefore, provides a good signal-to-noise ratio. Also, this property is available even during high gains.

In this article, we will discuss the MPSA18.

And it will enable you to figure out connections of the transistor in your circuits.  

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    MPSA18 Pinout Configuration


The MPSA18 NPN transistor is a decent transistor consisting of three pins.

Namely, the emitter, base, and collector are the pins present.

The TO-92 package encloses the main functional area of the MPSA18 transistor.

Moreover, the small size and efficiency make it the most preferred transistor for many electronic devices.

The table below describes each pin.

PIN Pin name Pin description
1 Emitter This pin connects to the ground. Also, it works as a channel that drains out the excess electrical current from the transistor.
2 Base This pin works by turning it on or off the transistor. Thereby controlling the biasing of the transistor.
3 Collector The collector pin connects the load; hence current from the power source flows to the load through the collector.

  three-pin transistor

 (three-pin transistor)


  1. Features or Technical Specifications.


The key features of an MPSA18 NPN transistor are;

  • The power transistor is an NPN transistor enclosed in a TO-92 package.
  • Secondly, the MPSA18 transistor has a maximum collector current(Ic) of 100mA and a maximum collector-emitter voltage of 45v.
  • Thirdly, the transistor has a maximum emitter-base voltage of 5v with a maximum collector dissipation of 625mW.
  • This NPN transistor also has a minimum and maximum DC gain between 400 and 1500.
  • Also, the low-power general-purpose transistor has a maximum 45V collector base with a maximum transition frequency of 100mHz.
  • Furthermore, these power transistors have maximum storage and operating temperatures between -55⁰C to 150⁰C.
  • Lastly, the MPSA18 transistors are low-noise transistors with a high gain.

  low-powered transistors in a T0-92 package type

(low-powered transistors in a T0-92 package type.)


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    Replacement and Equivalent

  You can replace the MPSA188 transistor with other transistors which have similar properties.

Some of these transistors include; 2N5089, 2N5088, FTSO&89, 2N5962, 2N5961, and NTE47.

However, alternative transistor pairs are 2N5210, MPS6602, BC550, BC547, BC548, BC549, MPS650, and BC109.

MPSA18 Pinout: different types of transistors

 (different types of transistors)


  1. MPSA18 Pinout: Where and How to Use The MPSA18 Transistor?


You can use the MPSA18 transistor in a wide range of amplifier applications.

Notably, its primary function is to amplify a low-gain signal to a high-gain signal.

It would help if you often strengthened these low-gain signals in audio preamplifiers and radio receiver circuits.

Also, any other low-level signals in electronic equipment may require this amplification.

In addition, you can use this device in many RF applications that work with a frequency below 100mHz.

Moreover, you can use it to switch applications.

The MPSA18 transistor particularly switches loads of up to 45v with only a load current of 100mA.

This property explains why this specific transistor is low-powered.

Additionally, you can trigger the transistor's base pin with a 7v power supply.

The 7v power supply helps to control the switching of the transistor.  

MPSA18 Pinout: Additional tip

When using any electrical equipment, you must keep it for long-life performance and reliability.

To ensure the longevity of this NPN transistor, always use it at least 20% below its maximum ratings.

For example, the MPSA18 transistor can handle a collector current of 100mA and a voltage of 45v.

Therefore, using a maximum load of 80mA with a voltage of 35v will help preserve its longevity.

Also, storing the electrical equipment in temperatures slightly above-55⁰C and below 150⁰C will help immensely.  

MPSA18 Pinout: a picture of a green computer circuit board transistors

(a picture of a green computer circuit board transistors.)


MPSA18 Pinout:

 (an MPSA18 transistor circuit diagram.)


  1. MPSA18 Pinout: MPSA18 Transistor Applications


  • Firstly, used in many slight signal amplification like sensing or detecting applications.
  • Secondly, in radio and radio frequency(RF) applications. These applications must require a transition frequency of 100mHz.
  • Thirdly, apply this signal amplifier transistor in audio recorders, voice recorders, and audio amplifier stages.
  • Moreover, the MPSA18 transistor is an essential electrical component in audio and preamplifiers.
  • Lastly, you need this device in applications on amplifier circuits that drive a load of under 100mA.

  MPSA18 Pinout: a photo of transistors

(a photo of transistors.)


We hope this article answers any of your MPSA18  transistor-related questions.

If you like it, please check out more articles from us.

Also, do not hesitate to contact us for additional information.    

Special Offer: $1 for 5 PCB Assemblies!

One requirement only: Order must be placed using a company account.
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