BC559 Transistor, Pinout, Equivalent, Uses, Feature and More

This post is all about understanding BC559 transistor, its pinout, equivalent, uses, feature and other technical details about this general purpose TO-92 package transistor.


BC559 Transistor, Pinout, Equivalent, Uses, Feature 



Features / technical specifications:

  • Package Type: TO-92
  • Transistor Type: PNP
  • Max Collector Current(IC): -100mA
  • Max Collector-Emitter Voltage (VCE): -30V
  • Max Collector-Base Voltage (VCB): -30V
  • Max Emitter-Base Voltage (VBE): -5V
  • Max Collector Dissipation (Pc): 500 Milliwatt
  • Max Transition Frequency (fT): 150 MHz
  • Minimum & Maximum DC Current Gain (hFE): 110 to 800
  • Max Storage & Operating temperature Should be: -65 to +150Centigrade


BC559 Transistor Explained / Description:

BC559 is a TO-92 package PNP transistor of BC55x series of PNP transistors. This series also contains other transistors which are BC556, BC557, BC558, and BC560. BC559 is also a general-purpose transistor like other transistors of BC55x series but it is little bit different in terms of specs as compare to the other transistors of the series. The maximum collector current of the transistor is -100mA, therefore, it can drive load of upto -100mA and the maximum collector to emitter voltage is -30V so the load voltage should be under -30V. The maximum collector power dissipation of the transistor is 500mA and the DC current gain (hFE) of the transistor is 110 to 800. However, the transistor is available in three different HFE values that can be determined by the alphabet after the transistor number. If the alphabet is “A” then the transistor gain value will be 110 – 220, if the alphabet is “B” then the transistor gain value will be 200 – 450 and if the alphabet is “C” then the transistor gain value will be 420 – 800

A Low Noise Transistor

Like other transistors in this series BC559 is also a low noise transistor and its typical to maximum noise figure is 1.2 to 4dB. Low noise can be a useful feature if you are using the transistor in an audio preamplifier circuit of any type of small signal amplification.


NPN Complementary:

NPN Complementary of BC559 is BC549


Replacement and Equivalent:

The exact match transistors for BC559 are BC556, BC557, BC558 and BC560 and works almost same if used in the place of BC559. Other nearest possible equivalents are, 2SA1016, 2SA1017, 2SA1082, 2N4403, A1015, A733, 2n2907, BC880, BC879, BC490, 2N5821, BC327. Pin configuration of the nearest possible equivalents can be different, so check the pins before replacing in a circuit.


Where We Can Use It & How to Use:

BC559 is a general-purpose transistor and can be used in wide variety of general-purpose switching and amplification purposes. As a switch it can drive load of upto 100mA which is quite appropriate to drive variety of load such as relays, high power transistors, ICs, LEDs, etc. As mentioned above it can also be used as an audio amplifier and also for audio preamplification purposes. Moreover, it can also be used for any type of small signal amplification. The maximum frequency of the transistor is 150MHz therefore it will also perform well in high frequency and also in RF circuits under 150MHz.



Audio amplifier

Any Signal Amplification


Darlington pair

RF circuits

Switching loads under 100mA


Safe Operating Guidelines / Absolute Maximum Ratings:

For safe operation, use the transistor 20% below its maximum rating. The maximum collector current is -100mA therefore do not drive load of more than 80mA, the maximum collector-emitter voltage is -30 so do not drive load of more than -24V and always store and operate this transistor in temperature above -65 °C and below +150 °C.



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