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BC547 Transistor is a general-purpose transistor mostly used in educational and electronics projects and It is also used in commercial circuits as well as in hobby projects. It is a tiny three-terminal device capable to convert small signal inputs into large amplified outputs. It is a BJT (Bipolar Junction Transistor) NPN transistor that comes in TO-92 packaging and it can handle 100mA output current. The transistor, BC 547 is shown below.
Bc547 transistor has three terminals Collector, Base, and Emitter. Pin detail is clearly shown in the figure given below.
The complement of BC547 is PNP BC557, BC558.
You can replace bc 547 with bc548, Bc549, 2N2222, 2N3904, 2N4401, and BC337. The Pin configuration of some transistors is different from BC547 so check the pin configuration before replacing it in a circuit.
The SMD of the BC547 is available as the BC847, BC847W, BC850, and BC850W.
A lot of applications are associated with BC547, a few of the main applications are given below.
For the long life of bc547 do not increase the load more than 100mA on it, and do not exceed the voltage across this transistor to 45V DC. Always use a relevant base resistor to provide the required current for saturation because more current on the base can damage the transistor. The temperature does not above +150 centigrade and below -65 centigrade. Always confirm the collector-emitter and base pins before placing them in the circuit. If accidentally placed wrong in a circuit then check its performance again because wrong input can decrease its efficiency.
In a switch, it is operated in the Saturation and Cut-Off Region. A transistor acts as an Open switch during forwarding and as a Closed switch during Reverse Bias, this biasing can only be achieved by supplying the required amount of current to the base pin of the transistor. As mentioned above the biasing current maximum of 5mA. More current than 5mA will kill the Transistor; so, a resistor is always added in series with a base pin. We can calculate the value of the resistor (RB) using the below formulae.
RB = VBE / IB
A transistor acts as an Amplifier while operating in Active Region. BC547 can amplify power, voltage, and current in different configurations.
Some configurations used in amplifier circuits are
The formula used for the amplifier: DC Current Gain = Collector Current (IC) / Base Current (IB)
First of all, We want to show you how can you use bc547 transistors in projects. We are going to show you a simple touch on the circuit by using 547. This will clear your concept of the working of transistors bc547,bc548bc549, and other transistors the same as this.
This simple circuit clearly shows that when you touch the points shown in the circuit. A small amount of + current flows through the figure from + to base and this small current turns on the transistor.