Direct connect 5V to the transistor

[yahootew3000]

how to connect a transistor to a 5v base

Hi, i would like to ask whether can i directly connect 5V to the base of transistor without the resistor?But i do not power it continously, instead, i'm using the PWM signal.Meaning to ON-OFF-ON the transistor rapidly. The transistor is 2N3904.
Can it last for long period of time?Thx.

 

[leotim]

It depends on transistor type, its specification and your voltage source type and pulse duration and period. In the transistor datasheet, there is a section called MAXIMUM RATINGS. Look in this section for maximum allowable Ib (base current). You should calculate if the base current goes near this value or not. Also, you should consider total power dissipation on the transistor not increase above MAXIMUM RATINGS.