{"product_id":"bc558-pnp-transistor","title":"Bc558 Pnp Transistor","description":"\u003cp\u003e\u003cstrong\u003eBC558\u003c\/strong\u003e is a \u003cstrong\u003ePNP transistor\u003c\/strong\u003e 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 \u003cstrong\u003ePNP transistor\u003c\/strong\u003e differs from a \u003cstrong\u003eNPN transistor\u003c\/strong\u003e.\u003c\/p\u003e\r\n\r\n\u003cp\u003e\u003cstrong\u003eBC558\u003c\/strong\u003e has a gain value of 110 to 800; this value determines the amplification capacity of the transistor. The peak current that could flow through the Collector pin is 200mA, this combined with the high gain value makes it an ideal choice for audio amplification applications.\u003c\/p\u003e\r\n\r\n\u003cp\u003eWhen this transistor is fully biased then it can allow continues current of 100mA to flow across the collector and emitter. This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (V­CE) or Base-Emitter (VBE) could be 200 and 900 mV respectively. 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.\u003c\/p\u003e\r\n\r\n\u003ch2\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003c\/h2\u003e\r\n\r\n\u003col\u003e\r\n\t\u003cli\u003eBi-Polar PNP Amplifier Transistor\u003c\/li\u003e\r\n\t\u003cli\u003eDC Current Gain (hFE) is 800 maximum\u003c\/li\u003e\r\n\t\u003cli\u003eContinuous Collector current (IC) is 100mA\u003c\/li\u003e\r\n\t\u003cli\u003ePeak Collector current (Ic) is 200mA\u003c\/li\u003e\r\n\t\u003cli\u003eEmitter Base Voltage (VBE) is 5V\u003c\/li\u003e\r\n\t\u003cli\u003eBase Current(IB) is 200mA peak\u003c\/li\u003e\r\n\t\u003cli\u003eAvailable in To-92 Package\u003c\/li\u003e\r\n\u003c\/ol\u003e\r\n\r\n\u003ch3\u003e\u003cstrong\u003eBC558 as switch\u003c\/strong\u003e\u003c\/h3\u003e\r\n\r\n\u003cp\u003eWhen a transistor is used as a switch it is operated in the Saturation and Cut-Off Region 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. A resistor is always added in series with base pin to limit the base current. The value of this resistor (RB) can be calculated using below formulae.\u003c\/p\u003e\r\n\r\n\u003cpre\u003e\r\nRB  = VBE \/ IB\u003c\/pre\u003e\r\n\r\n\u003cp\u003eWhere, the value of VBE should be 5V for BC558 and the Base current (IB) depends on the Collector current (IC).\u003c\/p\u003e\r\n\r\n\u003cp\u003e\u003cimg alt=\"PNP Transistor Switch Circuit\" data-entity-type=\"file\" data-entity-uuid=\"fdf21b74-9be0-4bdb-abec-92d42a0d4331\" src=\"https:\/\/components101.com\/sites\/default\/files\/inline-images\/PNP%20switch.gif\"\u003e\u003c\/p\u003e\r\n\r\n\u003cp\u003eAlso note that a PNP transistor is always used for high side switching, meaning the collector is connected to power and emitter to load that is to be switched.\u003c\/p\u003e\r\n\r\n\u003cp\u003e \u003c\/p\u003e\r\n\r\n\u003ch3\u003e\u003cstrong\u003eBC558 as Amplifier\u003c\/strong\u003e\u003c\/h3\u003e\r\n\r\n\u003cp\u003eA Transistors acts as an Amplifier when operating in Active Region. It can amplify power, voltage and current at different configurations.\u003c\/p\u003e\r\n\r\n\u003cp\u003eSome of the configurations used in amplifier circuits are\u003c\/p\u003e\r\n\r\n\u003col\u003e\r\n\t\u003cli\u003eCommon emitter amplifier\u003c\/li\u003e\r\n\t\u003cli\u003eCommon collector amplifier\u003c\/li\u003e\r\n\t\u003cli\u003eCommon base amplifier\u003c\/li\u003e\r\n\u003c\/ol\u003e\r\n\r\n\u003cp\u003e \u003c\/p\u003e\r\n\r\n\u003cp\u003eOf the above types common emitter type (which amplifies voltage) is the popular and mostly used configuration. The BC558 because of this large gain value is normally used to as a audio amplifier. Where an input signal of low voltage is amplified (switched) to high voltages t0 drive loads like speakers. In the below GIF you can notice the transistor being switched for a low voltage (1v) audio signal\u003c\/p\u003e\r\n\r\n\u003cp\u003e\u003cimg alt=\"BC558 Transistor Amplifier Circuit\" data-entity-type=\"file\" data-entity-uuid=\"1823e7a5-5bf2-445b-b1d9-e7eeecc8d666\" src=\"https:\/\/components101.com\/sites\/default\/files\/inline-images\/PNP%20AMplifier.gif\"\u003e\u003c\/p\u003e\r\n\r\n\u003cp\u003eWhen uses as an Amplifier the DC current gain of the Transistor can be calculated by using the below formulae\u003c\/p\u003e\r\n\r\n\u003cpre\u003e\r\nDC Current Gain = Collector Current (IC) \/ Base Current (IB)\u003c\/pre\u003e\r\n\r\n\u003cp\u003e \u003c\/p\u003e\r\n\r\n\u003ch3\u003e\u003cstrong\u003eApplications\u003c\/strong\u003e\u003c\/h3\u003e\r\n\r\n\u003cul\u003e\r\n\t\u003cli\u003eBuild simple audio circuits\u003c\/li\u003e\r\n\t\u003cli\u003eGeneral purpose amplifier \u003c\/li\u003e\r\n\t\u003cli\u003eDriver Modules like Relay Driver, LED driver etc..\u003c\/li\u003e\r\n\t\u003cli\u003eAmplifier modules like Audio amplifiers, signal Amplifier etc..\u003c\/li\u003e\r\n\t\u003cli\u003eDarlington pair\u003c\/li\u003e\r\n\u003c\/ul\u003e\r\n\r\n\u003cp\u003e \u003c\/p\u003e\r\n\r\n\u003ch3\u003e\u003cstrong\u003e2D model of the component\u003c\/strong\u003e\u003c\/h3\u003e\r\n\r\n\u003cp\u003eIf you are designing a PCB or Perf board with this component then the following picture from the Datasheet will be useful to know its package type and dimensions.\u003c\/p\u003e\r\n\r\n\u003cp\u003e\u003cimg alt=\"BC558 Transistor Dimensions\" data-entity-type=\"file\" data-entity-uuid=\"6e2e7975-1cc2-4f65-8195-6298ac976bd0\" src=\"https:\/\/digilog.pk\/cdn\/shop\/files\/BC558-Transistor-Dimensions.png\" data-original=\"https:\/\/components101.com\/sites\/default\/files\/inline-images\/BC558-Transistor-Dimensions.png\" loading=\"lazy\" data-files=\"BC558-Transistor-Dimensions.png\"\u003e\u003c\/p\u003e\r\n\r\n\u003ccenter\u003e\r\n\u003cp\u003e\u003cstrong\u003eComponent Datasheet\u003c\/strong\u003e\u003c\/p\u003e\r\n\r\n\u003cp\u003e\u003cstrong\u003e\u003ca href=\"https:\/\/components101.com\/sites\/default\/files\/component_datasheet\/BC558%20Datasheet.PDF\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Bc558 datasheet\" aria-label=\"Visit a webpage about Bc558 datasheet\"\u003eBC558 Datasheet\u003c\/a\u003e\u003c\/strong\u003e\u003c\/p\u003e\r\n\u003c\/center\u003e","brand":"China","offers":[{"title":"Default Title","offer_id":43962399653953,"sku":"B520,L100,Th50","price":6.0,"currency_code":"PKR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0727\/2805\/1777\/files\/BC558_PNP_Transistor.jpg?v=1779573676","url":"https:\/\/stem.pk\/products\/bc558-pnp-transistor","provider":"stem.pk","version":"1.0","type":"link"}