You may refer to the article 100 Watt transistor amplifier to see an example of the role of complementary transistor pairs in making a particular circuit more efficient. They all basically come under one roof, but are the “brothers” and the “sisters” of BC547, with the latter being the most commonly used.īC546, BC547, BC548, BC549 and BC550 are NPN types, while BC556, BC557, BC558, BC559 and BC560 are PNP types and form complementary pairs with the NPN type. The diagram shows the basic appearance of the transistor, which might differ slightly depending upon the particular make, however the technical specs and the pin-out assignments remain identical. Companies like NXP, PHILIPS, Micro Electronics, and FAIRCHILD, to name a few, are the leaders in manufacturing this device. They may be also classified by their frequency handling capabilities and their amplification determining factor or hFE.Ī BC547 is a general purpose, small signal transistor fit for almost all types of circuit applications and therefore extensively used for making an unlimited range of electronic gadgets today.

They are broadly distinguished by their power ratings or power handling capacities. Even the most sophisticated chips to date have (millions of) transistors embedded within them and configured into complex circuits, assigned with many discrete and specific operations through different stages.Īll transistors basically function in the same manner. A BC547 transistor is a tiny three terminal device capable of converting small signal inputs into large amplified outputs, probably one of the greatest inventions of mankind so far.

Bc557 vs bc547