2N3904 BJT NPN Transistor

The 2N3904 is another popular NPN bipolar junction transistor (BJT), similar to the BC547 but with some differences in its electrical characteristics. Here’s an overview of the 2N3904 transistor:
Type: NPN transistor.
Polarity: Like all BJTs, it has three terminals: Base (B), Collector (C), and Emitter (E).
Maximum Voltage Ratings:
Collector-Base Voltage (V_CBO): 60V
Collector-Emitter Voltage (V_CEO): 40V
Emitter-Base Voltage (V_EBO): 6V
Current Ratings:
Continuous Collector Current (I_C): 200 mA (milliamps)
Peak Collector Current (I_CM): 800 mA
Base Current (I_B): 50 mA
Power Dissipation:
Total Power Dissipation (P_tot): 625 mW (milliwatts)
Transition Frequency (f_T): Typically around 250 MHz.
Common Uses:
Amplification: Similar to the BC547, it is used in small signal amplification circuits due to its high current gain (hFE typically 100 to 300).
Switching: It can switch moderate currents and voltages.
Oscillator Circuits: It can be used in oscillator circuits at moderate frequencies.