S9018 High-Frequency, Low-noise NPN Bipolar Junction Transistor (BJT)

A NPN bipolar junction transistor rated at 30V collector-emitter and 50 mA collector current, used for high frequency amplification - its transition frequency of around 700 MHz makes it suitable for RF and oscillator circuits where general purpose transistors will not work. As a NPN device it sinks current to ground when its base is driven high. Always fit a base resistor when driving it from a microcontroller pin - connecting a base directly to a logic output will damage both. A common starting value is 1K for switching applications. 30V and 50 mA rating suits moderate loads; TO-92 through-hole package fits breadboards; Very low cost and widely documented; Standard pinout for the S9018 family