Hi everyone,
I am learning electronic theory so i can give my self a head start when i do electronic engineering at uni
But there is something i dont understand. Lets take for example a BC548 transistor. It has a max base current of 500ma. Ok, so lets say i want a current of 100ma on the base with a voltage of 9v, simple, use V = IR. So i get the value of a resistor needed to be 90 ohms.
Why do other websites use large resistances with the base?
Like if they have the output of a 4000 chip connected to the base they have a resistor in series > 5K ohms?
Whats going on, thanks
I am learning electronic theory so i can give my self a head start when i do electronic engineering at uni
But there is something i dont understand. Lets take for example a BC548 transistor. It has a max base current of 500ma. Ok, so lets say i want a current of 100ma on the base with a voltage of 9v, simple, use V = IR. So i get the value of a resistor needed to be 90 ohms.
Why do other websites use large resistances with the base?
Like if they have the output of a 4000 chip connected to the base they have a resistor in series > 5K ohms?
Whats going on, thanks