{"product_id":"bc557-transistor","title":"BC557 Transistor","description":"\u003ch4\u003e\u003cimg data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-364843 lazyloaded\" src=\"https:\/\/i0.wp.com\/makerselectronics.com\/wp-content\/uploads\/2016\/08\/BC557-Pinout.jpg?resize=700%2C480\u0026amp;ssl=1\" alt=\"\" width=\"700\" height=\"480\" data-src=\"https:\/\/i0.wp.com\/makerselectronics.com\/wp-content\/uploads\/2016\/08\/BC557-Pinout.jpg?resize=700%2C480\u0026amp;ssl=1\" data-eio-rwidth=\"700\" data-eio-rheight=\"480\"\u003e\u003c\/h4\u003e\n\u003ch5\u003e\n\u003cb\u003e\u003cstrong\u003eBC557 Pin \u003c\/strong\u003e\u003c\/b\u003e\u003cb\u003e\u003cstrong\u003eConfiguration\u003c\/strong\u003e\u003c\/b\u003e\n\u003c\/h5\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003ePin Number\u003c\/strong\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003ePin Name\u003c\/strong\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003eDescription\u003c\/strong\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e1\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eCollector\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eCurrent flows in through collector\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e2\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eBase\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eControls the biasing of transistor\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e3\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eEmitter\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eCurrent Drains out through emitter\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch5\u003e\u003cb\u003e\u003cstrong\u003eFeatures\u003c\/strong\u003e\u003c\/b\u003e\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003eBi-Polar PNP Transistor\u003c\/li\u003e\n\u003cli\u003eDC Current Gain (h\u003csub\u003eFE\u003c\/sub\u003e) is 300 maximum\u003c\/li\u003e\n\u003cli\u003eContinuous Collector current (I\u003csub\u003eC\u003c\/sub\u003e) is 100mA\u003c\/li\u003e\n\u003cli\u003eCollector-Emitter Voltage (V\u003csub\u003eCE\u003c\/sub\u003e) is 45V\u003c\/li\u003e\n\u003cli\u003eEmitter Base Voltage (V\u003csub\u003eBE\u003c\/sub\u003e) is 5V\u003c\/li\u003e\n\u003cli\u003eBase Current(I\u003csub\u003eB\u003c\/sub\u003e) is 5mA maximum\u003c\/li\u003e\n\u003cli\u003eAvailable in To-92 Package\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003eNote: \u003c\/strong\u003e\u003c\/b\u003eComplete Technical Details can be found at the \u003cb\u003e\u003cstrong\u003eBC557 datasheet\u003c\/strong\u003e\u003c\/b\u003e given at the end of this page.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003e\u003cstrong\u003eBrief Description on BC557 Transistor\u003c\/strong\u003e\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003eBC557\u003c\/strong\u003e\u003c\/b\u003e is a PNP transistor hence the collector and emitter will be closed (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\u003csub\u003eBE\u003c\/sub\u003e) as shown below\u003c\/p\u003e\n\u003cp\u003eBC557 has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. 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. To bias a transistor, we have to supply current to base pin, this current (I\u003csub\u003eB\u003c\/sub\u003e) should be limited to 5mA.\u003c\/p\u003e\n\u003cp\u003eWhen this transistor is fully biased then it can allow a maximum of 100mA to flow across the collector and emitter. This stage is called \u003cb\u003e\u003cstrong\u003eSaturation Region\u003c\/strong\u003e\u003c\/b\u003e and the typical voltage allowed across the Collector-Emitter (V­\u003csub\u003eCE\u003c\/sub\u003e) or Base-Emitter (V\u003csub\u003eBE\u003c\/sub\u003e) could be 200 and 900 mV respectively. When base current is removed the transistor becomes fully off, this stage is called as the \u003cb\u003e\u003cstrong\u003eCut-off Region\u003c\/strong\u003e\u003c\/b\u003e and the Base Emitter voltage could be around 660 mV.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003e\u003cstrong\u003eBC557 Transistor as switch\u003c\/strong\u003e\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp\u003eWhen a transistor is used as a switch it is operated in the \u003cb\u003e\u003cstrong\u003eSaturation and Cut-Off Region\u003c\/strong\u003e\u003c\/b\u003e 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\u003csub\u003eB\u003c\/sub\u003e) can be calculated using below formulae.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003eR\u003csub\u003eB  \u003c\/sub\u003e= V\u003csub\u003eBE\u003c\/sub\u003e \/ I\u003csub\u003eB\u003c\/sub\u003e\u003c\/strong\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003eWhere, the value of V\u003csub\u003eBE\u003c\/sub\u003e should be 5V for BC557 and the Base current (I\u003csub\u003eB\u003c\/sub\u003e depends on the Collector current (I\u003csub\u003eC\u003c\/sub\u003e). The value of I\u003csub\u003eB \u003c\/sub\u003eshould not exceed mA.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003e\u003cstrong\u003eBC557 Transistor as Amplifier\u003c\/strong\u003e\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp\u003eA Transistor acts as an Amplifier when operating in \u003cb\u003e\u003cstrong\u003eActive Region\u003c\/strong\u003e\u003c\/b\u003e. It can amplify power, voltage and current at different configurations.\u003c\/p\u003e\n\u003cp\u003eSome of the configurations used in amplifier circuits are\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eCommon emitter amplifier\u003c\/li\u003e\n\u003cli\u003eCommon collector amplifier\u003c\/li\u003e\n\u003cli\u003eCommon base amplifier\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eOf 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\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e\u003cstrong\u003eDC Current Gain = Collector Current (I\u003csub\u003eC\u003c\/sub\u003e) \/ Base Current (I\u003csub\u003eB\u003c\/sub\u003e)\u003c\/strong\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003e\u003cstrong\u003eApplications\u003c\/strong\u003e\u003c\/b\u003e\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003eDriver Modules like Relay Driver, LED driver etc..\u003c\/li\u003e\n\u003cli\u003eAmplifier modules like Audio amplifiers, signal Amplifier etc..\u003c\/li\u003e\n\u003cli\u003eDarlington pair\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Robot Pi Shop","offers":[{"title":"Default Title","offer_id":41522335645829,"sku":"TT-000035-DVR","price":0.2,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0565\/5819\/0725\/files\/bc557.png?v=1771406132","url":"https:\/\/robotpishop.com\/products\/bc557-transistor","provider":"Robot Pi Shop","version":"1.0","type":"link"}