This article describes the BC547 NPN transistor, its pinout, equivalents and operating principles, and its application in various electronic devices. It comes primarily in a TO-92 or advanced TO-226 package. The maximum output current this semiconductor device can handle is 100mA.

It also has very good gain (up to 800 hFE) and low noise (up to 10 dB), making it ideal for primary signal amplification stages. Its ability to operate in the 300 MHz band allows it to be called high-frequency. Typical saturation voltage is only 90mV, which is a definite advantage when used in circuits as a switch