MPSA42 bipolar junction NPN transistor 

MPSA42 NPN BJT transistor
MPSA42 NPN BJT transistor

MPSA42 is a bipolar junction NPN type transistor had more applications on high voltage applications, higher voltage values between the terminals make this transistor suitable for general purpose and other circuit applications.

MPSA42 transistor features

  • MPSA42 is NPN BJT transistor
  • Collector to emitter voltage (VCE) – 300V
  • Collector to base voltage (VCB) – 300V
  • Emitter to base voltage (VEB) – 6V
  • Peak collector current (IC) – 500mA
  • Maximum current gain – 25 to 40hFE
  • Junction temperature (TJ) – –55 to +150°C
  • Transition frequency (TF) – 50MHz
  • Collector cutoff current (ICBO) – 1µA
  • Collector to emitter saturation voltage (VCE (sat)) – 5V

MPSA42 transistor Pinout details 

MPSA42 transistor PINOUT details 
MPSA42 transistor PINOUT details

PIN1 – Emitter

PIN2 – Base

PIN3 – Collector

The Pinout implement at the MPSA42 NPN transistor is a common EBC configuration, and the transistor package used at this transistor is TO-92, it is a transistor package made with plastic and epoxy material.

The power dissipation at TO-92 is intermediate but the voltage capacity is high, so this is why TO-92 is used on MPSA42.

MPSA42 transistor description

MPSA42 transistor is popularly known as the high voltage transistor, the applications of MPSA42 transistor include general purpose and higher level such as video output and other high voltage applications.

Maximum collector to emitter voltage is 300V, collector to base voltage is 300V, and emitter to base voltage is 6V. The high voltage values at each terminal make this transistor a high voltage device.

The peak collector current value at the transistor is 500mA, the collector current value indicates the maximum allowable load on the MPSA42 transistor.

Power dissipation at MPSA42 is 625Mw, the power dissipation is also the temperature produced at the transistor.

The maximum current gain for the MPSA42 transistor is 25 to 40hFE, gain value is very important for a transistor at the signal magnifying process.

The junction temperature value at MPSA42 is -55 to +150°C, this will indicate the temperature range of the transistor.

The transition frequency of MPSA42 is 50MHz, the frequency value is important for switching applications.

MPSA42 Equivalent transistors

The transistor such as 2N6516, 2N6517, BFR88, BFR89, MPSD01, FTSOA42, PE7059, ZTX457, and MPSW42.

Each of the transistors is the equivalent for MPSA42, before selecting the transistor for a replacement, we need to consider PINOUT details and electrical values.

The transistor on the above list is the perfect equivalent for MPSA42, but the PINOUT details and voltage values are a little bit different, so check and verify.

MPSA42 SMD versions


The MMBTA42, PZTA42, and KST42 are the SMD version transistor for MPSA42, and also the electrical specifications of the SMD version transistor are the same as the MPSA42 transistor.

The difference in electrical specifications for MPSA42 SMD versions is at power dissipation.

MMBTA42 (PD = 240mW)

PZTA42 (PD) = 1000mW)

SMD Package of MMBTA42 and PZT42 transistors

The package used on the MPSA42 transistor SMD versions are,

MMBTA42 (SOT 23 3L)

PZTA42 (SOT 223 4L)

KST42 (SOT 23 3L)

 MPSA42 vs BFR88

The table below is for to compare MPSA42 vs BFR88 transistors electrical characteristics.

Characteristics  MPSA42   BFR88
Collector to base voltage (VCB) 300V 250V
Collector to emitter voltage (VCE) 300V 250V
Emitter to base voltage (VEB) 6V 5V
Collector current (IC) 500mA 0.2A
Power dissipation 625mW 0.8W
Junction temperature (TJ) -55 to +150°C -55 to 150°C
Transition frequency (FT) 50MHZ 130MHZ
     Noise (N)
   Gain (hFE) 25 to 40hFE 20hFE
    Package TO-92 TO-92


From the comparison between MPSA42 vs BFR88, it is confirmed that the voltage value is different, MPSA42 has a maximum of 300v, but at BFR88 it is 250.

And the current value at MPSA42 is 500mA, but for BFR88 it is 200mA

The power dissipation of both are different, for MPSA42 it is 625Mw, but for BFR88 it is 0.8w.

The transition frequencies of both transistors are very much different because for MPSA42 it is 50MHz, but for BFR88 it is 130MHz.

MPSA42 graphical characteristics

MPSA42 graphical characteristics
MPSA42 graphical characteristics

The figure shows the DC current gain vs Collector current characteristics, the plotted curve indicates the range of temperature withstanding capability of the transistor, without any change in gain and current value.

MPSA42 graphical characteristics
MPSA42 graphical characteristics

The figure shows the base-emitter voltage vs collector current curve, here we can see the increase in voltage and current values did not affect temperature.

Applications of MPSA42 transistor

Technically MPSA42 transistor is a HIGH VOLTAGE device so, naturally, applications based on MPSA42 transistor runs with high voltage, the circuit like switching, controlling, battery charger, voltage booster, and inverter based on MPSA42 rated as high voltage.

  • Voltage booster circuit
  • Inverter applications
  • Switching high voltage load
  • Control load with high voltage
  • Speed control of motors
  • UPS circuit applications
  • Battery charger circuits
  • Power supply circuit application

 These are the applications based on the MPSA42 transistor, we explain some of the main circuits based on the MPSA42 transistor, and this will help you to understand the nature of the MPSA42 transistor.

MPSA42 voltage booster circuit

MPSA42 voltage booster circuit
MPSA42 voltage booster circuit

The figure shows the voltage booster circuit, this is not the complete circuit, and it is the main section of the voltage booster using the MPSA42 transistor.

When the input signal passes through the input, the MPSA42 transistor magnifies the signal to a higher level and produces boosted voltage value.

The maximum voltage at the MPSA42 is 300v, so the signal voltage will be on that limit.


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