{"product_id":"bc557-pnp-transistor","title":"BC557 PNP Transistor","description":"\u003cdiv id=\"content_description\" class=\"ty-wysiwyg-content content-description\"\u003e\n\u003cdiv\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003eBrief Description on BC557 Transistor\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cstrong\u003eBC557\u003c\/strong\u003e is a PNP transistor hence the collector and emitter will be close (Forward biase) when the base pin is hold at ground and will be open (Reverse biase) when a signal is provide 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\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0965\/3623\/2249\/files\/BC557_working.gif?v=1789233524\" alt=\"BC557 transistor working circuit simulation\" width=\"514\" height=\"289\" loading=\"lazy\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\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\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003eWhen this transistor is fully biase then it can allow a maximum of 100mA to flow across the collector and emitter. This stage is call \u003cb\u003eSaturation Region\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 remove the transistor becomes fully off, this stage is called as the \u003cb\u003eCut-off Region\u003c\/b\u003e and the Base Emitter voltage could be around 660 mV.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3 style=\"font-weight: 500;\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003eBC557 Pin \u003c\/strong\u003e\u003c\/b\u003e\u003cb\u003e\u003cstrong\u003eConfiguration\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003ctable style=\"font-weight: 400;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd width=\"64\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003ePin Number\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"122\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003ePin Name\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"429\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003eDescription\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"64\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e1\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"122\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eCollector\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"429\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eCurrent flows in through collector\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"64\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e2\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"122\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eBase\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"429\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eControls the biasing of transistor\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"64\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e3\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"122\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eEmitter\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd width=\"429\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eCurrent Drains out through emitter\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3 style=\"font-weight: 500;\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003eFeatures\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul style=\"font-weight: 400;\"\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eBi-Polar PNP Transistor\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eDC Current Gain (h\u003csub\u003eFE\u003c\/sub\u003e) is 300 maximum\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eContinuous Collector current (I\u003csub\u003eC\u003c\/sub\u003e) is 100mA\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eEmitter Base Voltage (V\u003csub\u003eBE\u003c\/sub\u003e) is 6V\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eBase Current(I\u003csub\u003eB\u003c\/sub\u003e) is 5mA maximum\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eAvailable in To-92 Package\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003eBC557 Transistor as switch\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003eWhen a transistor is use as a switch it is operate in the \u003cb\u003eSaturation and Cut-Off Region\u003c\/b\u003e as explain in above paragraph. As discussed a transistor will act as an Open switch during Forward Bias and as a Close switch during Reverse Bias, this biasing can be achieved by supplying the require 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 calculate using below formulae.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp align=\"center\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003eR\u003csub\u003eB  \u003c\/sub\u003e= V\u003csub\u003eBE\u003c\/sub\u003e \/ I\u003csub\u003eB\u003c\/sub\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\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\/span\u003e\u003c\/p\u003e\n\u003ch3 style=\"font-weight: 500;\"\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e\u003cstrong\u003eBC557 Transistor as Amplifier\u003c\/strong\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp style=\"font-weight: 400;\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eA Transistors 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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"font-weight: 400;\"\u003e\u003cspan style=\"font-size: 28px;\"\u003eSome of the configurations use in amplifier circuits are\u003c\/span\u003e\u003c\/p\u003e\n\u003col style=\"font-weight: 400;\"\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eemitter amplifier\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eCommon collector amplifier\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003ebase amplifier\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp style=\"font-weight: 400;\"\u003e\u003cspan style=\"font-size: 28px;\"\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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"font-weight: 400;\"\u003e\u003cspan style=\"font-size: 28px;\"\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\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003eApplications\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eDriver Modules like Relay Driver, LED driver etc..\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003eAmplifier modules like Audio amplifiers, signal Amplifier etc..\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 28px;\"\u003e Darlington pair\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cspan style=\"font-size: 28px;\"\u003eDatasheet\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0965\/3623\/2249\/files\/BC557_Datasheet.pdf?v=1789233530\"\u003ehttps:\/\/components101.com\/sites\/default\/files\/component_datasheet\/BC557%20Datasheet.pdf\u003c\/a\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cb\u003e2D model of the component\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003eIf you are designing a PCD or Perf board with this component then the following picture from the \u003cstrong\u003eBC557 Datasheet \u003c\/strong\u003ewill be useful to know its package type and dimensions.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"font-size: 28px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0965\/3623\/2249\/files\/BC557-Dimensions.png?v=1789233528\" alt=\"BC557 Transistor Dimensions\" width=\"537\" height=\"332\" loading=\"lazy\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Electronics Hub","offers":[{"title":"Default Title","offer_id":54466803269945,"sku":"product-6260","price":4.0,"currency_code":"PKR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0965\/3623\/2249\/files\/1-1024x683-1-1.jpg?v=1789233535","url":"https:\/\/electronicshub.pk\/products\/bc557-pnp-transistor","provider":"Electronics Hub","version":"1.0","type":"link"}