Anything more than 5mA will kill the Transistor hence a resistor is always added in series with base pin. As mentioned the biasing current should maximum of 5mA. As discussed a transistor will act as an Open switch during Forward Bias and as a Closed switch during Reverse Bias, this biasing can be achieved by supplying the required amount of current to the base pin. When a transistor is used as a switch it is operated in the Saturation and Cut-Off Region as explained above. When base current is removed the transistor becomes fully off, this stage is called as the Cut-off Region and the Base Emitter voltage could be around 660 mV. This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (V CE) or Base-Emitter (V BE) could be 200 and 900 mV respectively.

When this transistor is fully biased then it can allow a maximum of 100mA to flow across the collector and emitter. To bias a transistor we have to supply current to base pin, this current (I B) should be limited to 5mA. The maximum amount of current that could flow through the Collector pin is 100mA, hence we cannot connect loads that consume more than 100mA using this transistor.

Note: Complete Technical Details can be found at the BC547 datasheet given at the end of this page.īC549, BC636, BC639, 2N2222 TO-92, 2N2222 TO-18, 2N2369, 2N3055, 2N3904, 2N3906, 2SC5200īC547 transistor has a gain value of 110 to 800, this value determines the amplification capacity of the transistor.

Continuous Collector current (I C) is 100mA.

BC547 is a 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 base pin.

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