BC308 Transistor Pinout, Equivalent, Applications, Features, Safe Operating Guidelines

BC308 is a PNP BJT transistor available in TO-92 package. In this post we will understand BC308 transistor pinout, equivalent, applications, features, electrical characteristics, safe operating guidelines and other details of this component.

 

Absolute Maximum Ratings:

• Package Type: TO-92
• Transistor Type: PNP
• Max Collector Current(I_C): -100mA
• Max Collector-Emitter Voltage (V_CEO): -25V
• Max Emitter-Base Voltage (V_EBO): -5V
• Max Collector Power Dissipation (Pc): 500 milliwatt
• Max Transition Frequency (f_T): 130 MHz
• Minimum & Maximum DC Current Gain (h_FE): 120 – 800
• Max Storage & Operating temperature Should Be: -55 to +150 Centigrade

 

NPN Complementary:

NPN Complementary of BC308 is BC238

 

Replacement and Equivalent:

BC557, BC556, BC560 (The pin layout of these alternative transistors may be different so check their pin layout before replacing in your circuit.)

 

BC308 Transistor Explained / Description:

BC308 is quite an interesting PNP bipolar junction transistor (BJT) available in TO-92 package. It is a transistor of BC30x series which also contains other transistor such as BC307 and BC309. The transistor is designed to use in switching and amplification applications but due to its good overall electrical characteristics, it can also be used in variety of other applications.

Looking at the pinout of the transistor the first pin of the transistor is Collector, second pin is Base and the third pin is Emitter.

The absolute maximum ratings of the transistor are as follows:

The maximum collector current is 100mA, max collector-emitter voltage is -25V, max emitter-base voltage is -5V, max collector power dissipation is 500mW and minimum and maximum storage and operating temperature is -55°C to 150°C.

The electrical characteristics of the transistor are also very interesting. The max noise figure of the transistor is 10dB, minimum to maximum DC current gain of the transistor is 120 to 800, max transition frequency is 130MHz and collector-emitter saturation voltage typically is -0.5V and max 0.3V.

BC308 is also available in three different versions according to its hFE values and can be determined with the alphabet written after the part number. So before purchasing first check what is your DC current gain requirement and then purchase the one with your required hFE value. So the hFE value of BC308 can be determined with the help of the alphabet written after the part number. The transistor that has written alphabet “A” after the part number its hFE value will be from 120 to 220, if the alphabet is “B” then the gain value will be 180 to 460 and if the alphabet is “C” then its hFE value will be 380 to 800.

 

Where We Can Use it & How to Use:

As discussed above BC308 transistor is designed to be used in switching and amplification applications but due to its good electrical characteristics it can also be used in variety of other applications such as RF circuits, sensor circuits, etc. It can also be used as an alternative to popular general purpose transistors such as BC557, 2N3906, etc.

 

Applications:

Signal Amplification Circuits

Audio Preamplifier Circuits

Sensor Circuits

RF Circuits

Audio amplifier circuits

Audio Amplifier Stages

Darlington Pairs

Switching Loads under -100mA

 

Safe Operating Guidelines:

Below are the safe operating guidelines for the transistor.

• Always check the pin layout before using it in your circuit.
• Do not exceed the absolute maximum ratings and always stay 20% below from these ratings.
• The maximum collector current of the transistor is -100mA but according to the 20% rule above we will only drive the load of -80mA.
• Same as the maximum collector-emitter voltage is -25V but following the 20% rule we will not go above 20V, which means we will only drive load that requires less than 20V.
• The storage temperature of the transistor should be between -55°C to 150°C.
• The junction temperature should be under 150°C.

 

Datasheet:

To download the datasheet just copy and paste the below link in your browser.

https://www.mouser.com/datasheet/2/308/BC309-1190467.pdf