BC557 - PNP晶体管

BC557 PinConfiguration

Pin Number	Pin Name	Description
1	集电极	电流通过收集器流入
2	Base	Controls the biasing of transistor
3	Emitter	Current Drains out through emitter

Features

• 双极PNP晶体管
• DC Current Gain (h_FE) is 300 maximum
• Continuous Collector current (I_C) is 100mA
• Emitter Base Voltage (V_BE）是6V.
• Base Current(I_B) is 5mA maximum
• Available in To-92 Package

Note:可以找到完整的技术细节BC557 datasheetgiven at the end of this page.

BC557 Equivalent PNP Transistors

BC157，BC558,2N3906,2SA1943, BD140,S8550, TIP127, TIP42

BC557晶体管的简要说明

BC557is aPNP transistor因此,收集器和发射器将关闭(Forward biased) when the base pin is held at ground and will be opened (Reverse biased) when a signal is provided to base pin. This is where a PNP transistor differs from a NPN transistor, a Logic state (blue colour) is used to toggle between Ground and Signal Voltage (Emitter-Base Voltage V_BE) as shown below

BC557具有110至800的增益值，该值确定晶体管的放大容量。可以通过收集器引脚流过的最大电流量为100mA，因此我们无法使用该晶体管消耗超过100mA的负载。偏压晶体管，我们必须向基本销提供电流，这个电流（i_B) should be limited to 5mA.

When this transistor is fully biased then it can allow a maximum of 100mA to flow across the collector and emitter. This stage is calledSaturation Regionand the typical voltage allowed across the Collector-Emitter (V_CE）或碱 - 发射器（v_BE) could be 200 and 900 mV respectively. When base current is removed the transistor becomes fully off, this stage is called as the截止地区and the Base Emitter voltage could be around 660 mV.

BC557晶体管作为开关

当晶体管用作开关时，它在其上操作饱和和截止区域as explained above. 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. As mentioned the biasing current should maximum of 5mA. Anything more than 5mA will kill the Transistor; hence a resistor is always added in series with base pin. The value of this resistor (R_B) can be calculated using below formulae.

R_B= V_BE/ I_B

在哪里，v的值_BEshould be 5V for BC557 and the Base current (I_Bdepends on the Collector current (I_C）。我的价值_Bshould not exceed mA.

BC557 Transistor as Amplifier

在操作时，晶体管充当放大器活跃地区. It can amplify power, voltage and current at different configurations.

Some of the configurations used in amplifier circuits are

1. Common emitter amplifier
2. Common collector amplifier
3. 公共基本放大器

Of the above types common emitter type is the popular and mostly used configuration. When uses as an Amplifier the DC current gain of the Transistor can be calculated by using the below formulae

DC Current Gain = Collector Current (IC) / Base Current (IB)

Applications

• Driver Modules like Relay Driver, LED driver etc..
• Amplifier modules like Audio amplifiers, signal Amplifier etc..
• Darlington pair

2D Model and Dimensions

如果您使用此组件设计PCD或PERF板，则来自以下图片BC557 Datasheetwill be useful to know its package type and dimensions.