2N3702 Transistor

The 2N3702 is a PNP Transistor with VCE of -25V and a collector current of 500mA. It can be used as a small signal switching transistor and any other small-signal application. It also has a low base voltage of -5V.

 

2N3702 Pinout Configuration

Pin Number	Pin Name	Description
1	Emitter	Electrons emitted from the emitter into the first PN junction
2	Collector	Electrons Emitted from Emitter Collected by the Collector
3	Base	Controls the biasing of the transistor

 

 Features & Specifications 

• Bi-Polar PNP Transistor
• DC Current Gain (hFE) is in between 60 - 300 maximum
• Continuous Collector current (IC) is 300mA
• Emitter Base Voltage (VBE) is -5V
• Available in TO-92 Package
• Maximum Collector-Base Voltage |Vcb|: -40 V
• Collector Dissipation: 0.625 W
• Transition Frequency:1 MHz
• Operating Junction Temperature Max (Tj): 175 °C
• Operating and Storage Junction Temperature Range -55 to +150 °C
• Collector Capacitance 100pF

 

Note: Complete Technical Details can be found in the 2N3702 Transistor datasheet given at the end of this page.

 

2N3702  Equivalent Transistor

2N3703, BC108, BC558,2N3072,S8550, 2SA1943

 

General Description of 2N3702 Transistor

The 2N3072 is a PNP Transistor, hence we need to provide zero volts to the base of the transistor to turn it on. This transistor comes with many different versions, if you are using this transistor as an amplifier make sure you check the gain of the transistor from the datasheet that can be found down below, because of different versions the gain value differs which can completely ruin your calculations. The maximum collector current of this transistor is rated at -500mA with a peak current of -600mA, this transistor has an emitter-base voltage of -5V. This transistor has a collector-emitter voltage of -25V and a collector base voltage of -40V. This transistor can operate with 150*C.

 

When this transistor is in a biased condition, then it can allow a maximum current of 500mA across CE(Collector-Emitter) Junction, this state of the transistor is called the saturation state, and driving a load that consumes more current than 500mA may damage the device in this condition. As you already may know a transistor is a current-controlled device so when the base current is removed the transistor becomes fully off, in this stage the transistor is working in its Cut-off Region and the Base Emitter voltage could be around 660 mV.

 

2N3072 Transistor has a gain of 60 to 300, this value determines the amplification capacity of the transistor. The peak current that can be flown through this transistor is 600maA, which combines with the gain value makes this transistor a perfect choice for a preamplifier or an audio amplifier.

 

How to use 2N3702 Transistor

Transistors are current-controlled devices so to turn them on/off a little current is needed. For the 2N3072 Transistor, this current is less than 2mA, a 2N3072 is a PNP transistor that means it will be on when the base is connected to the ground, and it will be off when a positive voltage is applied to the base of the transistor.

 

The simulated circuit above shows how this transistor behaves when the base of the transistor is pulled up to the VCC to the supply with a pullup resistor. As you can observe the transistor is off and the motor is not spinning.

            

When we turn on the transistor by connecting the base to the ground(in our case we have used a 0V probe in proteus) the transistor will remain on unless the voltage at the base of the transistor reaches more than the base turns off voltage (for this transistor, it is somewhere in between 0.7 -0.9V). The base of the transistor cannot be left floating otherwise there could be false triggering, which may lead to issues in the circuit. To resolve the issue, we need to add pullup resistors as shown in the example, a 10K resistor is used to pull up the base of the transistor to VCC.

 

Applications

• Build simple audio circuits
• General-purpose amplifier
• Driver Modules like Relay Driver, LED driver, etc.
• Amplifier modules like Audio amplifiers, signal Amplifiers, etc.
• Darlington pair

 

2D Model and Dimensions

If you are designing a PCB or Perf board with this component then the following picture from the Datasheet will be useful to know its package type and dimensions.