Bd140 transistor
Bd140 transistor

BD140 Transistor specification

  • It is a Bipolar PNP Transistor
  • DC Current Gain range is 25 to 250hFE
  • Collector current (IC) is -1.5A
  • Collector to base Voltage (VCB) is -80V
  • Collector to emitter voltage (VCE) is -80v
  • Emitter to base voltage (VEB) is -5V
  • Junction temperature (TJ) is 150°C
  • Base Current (IB) is -0.5A
  • Power dissipation at the transistor is 12.5W
  • Transition frequency (FT) is 190MHz 

BD140 pinout

BD140 pinout
BD140 pinout
Pin Number Pin Name Description
1 Emitter The current flows through the emitter
2 Collector Current flow through the collector
3 Base   The base trigger the transistor


TO-126 Package

The package used at the BD140 transistor in the TO-126 package is a rectangular-shaped transistor package.

Plastic and epoxy are used to make this TO-126 package, most of the time transistors with moderate current and high power dissipation use this transistor package.

The TO-126 transistor package weighs less and is compact to the device circuit, at the package we can spot a hole for attaching the heat sink into it.

BD140 Description

A bd140 transistor is a PNP transistor that works with the medium power, the moderate current device at the circuits, and the applications based on bd140 are at project allied circuits.

The total gain at the bd140 transistor is from the value 25 to 250hFE, the peak current gain value is very important on the applications like amplifiers and voltage regulators.

The collector current at the bd140 transistor is -1.5A, the negative at the current value indicates it is a PNP transistor, but the maximum collector current represents the peak load allowable on the bd140 transistor, at the circuits like amplifiers and h-bridge utilize this specification.

The base current at the bd140 is -0.5A, the maximum allowable base voltage to trigger the transistor.

The power dissipation at the bd140 device is 12.5W, this particular value indicates the peak value of power dissipation allowable on to a transistor and the to-126 transistor package is good at power dissipation.

The transition frequency on the bd140 transistor is 190MHZ, it is the main thing at the switching circuits.

The junction temperature of the bd140 transistor is 150°C.

Bd140 datasheet 

Bd140 datasheet 
Bd140 datasheet

If you need the datasheet in pdf please click this link

Bd140 transistor Equivalent

The bd140 transistor had the number of an equivalent transistor such as bd238g, mje171, mje702, bd792, mje252, and mje254.

Each equivalent transistor in this list is very much similar to each other, the electrical and physical specifications of all transistors are the same.

At the same time, we need to evaluate each transistor’s voltage and current value before going to replace bd140 with any of them.

Bd140 vs bd139 vs bd136 vs mje702

The transistor at the table is a list of transistors that is similar to the bd140 transistor, this comparison table will give you a wider idea about the electrical characteristics of each transistor.

At the list, we compare bd140 vs bd139, both of the transistors are the complementary pair, and then bd136 vs mje702, most of the electrical specifications of these transistors is similar to bd140.

Characteristics Bd140 Bd139 (NPN) Bd136 Mje702
Collector to base voltage (VCB)-80V80V-45V-80V
Collector to emitter voltage (VCE) -80V80V-45V-80V
Emitter to base voltage (VEB)-5V5V-5V-5V
Collector current (IC)-1.5A1.5A-1.5A-4A
Power dissipation 12.5W12.5W12.5W40W
Junction temperature (TJ)150°C150°C150°C150°C
Transition frequency (FT)190MHZ190MHZ190MHZ-
Noise (N)----
Gain (hFE)25 to 250hFE25to 250hFE10 to 250hFE750Hfe
Package TO-126TO-126TO-126TO-126

Bd140 transistor uses

  • Amplifier circuits
  • Switching circuits
  • Arduino projects
  • Motor driver circuits
  • Multi-vibrator circuits

 bd139 bd140 amplifier

bd139 bd140 amplifier
bd139 bd140 amplifier

The figure shows an amplifier circuit using bd140 and bd139 transistors, the amplifier circuits consist of one push-pull transistor pair, that is bd139 and bd140.

Then a preamp is at the circuit using bd139 transistor, then two diodes for the reverse current protection.

When the audio signal reaches the circuit, the preamp initially amplifies and passes over to the push-pull pair.

The complementary transistor amplifies the audio signal and produces an amplified audio signal.

Bd140 Arduino  

Bd140 Arduino  
Bd140 Arduino

The figure shows the h-bridge motor control circuit using the bd140 transistor and its complementary pair.

The motor driver project consists of two pairs of bd140 and bd139 transistors also known as the h-bridge network, and a two bc547 transistor for controlling input signal towards the h-bridge from the Arduino board.

The circuit with the trigger pulse passes from the Arduino board, the duty of the h-bridge on the operation of the motor is to control the speed and provide proper power to run the motor.

Bd140 transistor price

  • The Bd140 is a moderate current, low voltage PNP transistor device, which had more applications at hobby circuits.
  • The price for a bd140 transistor is 8rupees per piece or 0.12USD dollars.

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