BC549 Pin Description

Features

• General Purpose Low current and Low voltage NPN Transistor
• Current Gain (hFE), 420 to 800
• Continuous Collector current (IC) is 100mA
• Collector-Emitter voltage (VCEO) is 30 V
• Collector-Base voltage (VCB0) is 30V
• Emitter Base Voltage (VBE0) is 5V
• Transition Frequency 100MHz
• Available in To-92

Brief Description of BC549 Transistor

BC549 is an NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to the base pin. It is a low-current transistor hence the maximum amount of current that could flow through the Collector pin (Ic) is 100mA, hence we cannot connect loads that consume more than 100mA and load voltage of more than 30V using this transit. BC549 has a decent gain value of from 420 to 800; this value determines the amplification capacity of the transistor.

When this transistor is fully biased it can allow a maximum of 100mA to flow across the collector and emitter. This stage is called the Saturation Region. When the base current is removed the transistor becomes fully off, this stage is called the Cut-off Region.

Where to use BC549 Transistor?

The BC549 has a very low Continuous current of 100mA hence it cannot be used to switch heavy loads. But since it has a base trigger voltage of only 5V it can be easily controlled through 5V GPIO pins of Microcontrollers and Microprocessors. So it can be used in places where the load current is less than 100mA.

Apart from that the transistor can be used as an amplifier since it has a gain value from 420 to 800 and a transition frequency of 10MHz

Applications

• Switching small loads
• Small signal amplifiers
• Darlington pair
• The LED array sequence controller
• Audio Noise filters