Circuit Symbol and Conventions of N-P-N and P-N-P

• The block diagram and conventional circuit symbols of npn and pnp bipolar transistors are as show in Fig.

Fig.Circuit symbols and conventions of a bipolar transistor

• The arrowhead is always placed on the emitter terminal and it indicates the direction of flow of the conventional emitter current.
• For the npn transistor the emitter current flows out of the emitter terminal whereas for the pnp transistor the emitter flows into the emitter terminal.
• The current direction for all the other current components have been shown. Note that all these are the conventional currents.