Hi
Here is a very basic question for you,
I have a project and i want to make a circuit that uses the audio signal from the pc and display it.
I got an amplifier and bandpass filters etc... figured out but i need to use the output of this to drive a high voltage transistor (MJE340 NPN transistor).
My display must range between 0 and 20 mA.
So the base of the transistor is connected with the output of the bandpass filters, but how do i modulate the current for the display?
I know the more voltage at the base, the more current that is going to flow through the transistor but what are the formulas and how to calculate this?
Thank you so very much!
Here is a very basic question for you,
I have a project and i want to make a circuit that uses the audio signal from the pc and display it.
I got an amplifier and bandpass filters etc... figured out but i need to use the output of this to drive a high voltage transistor (MJE340 NPN transistor).
My display must range between 0 and 20 mA.
So the base of the transistor is connected with the output of the bandpass filters, but how do i modulate the current for the display?
I know the more voltage at the base, the more current that is going to flow through the transistor but what are the formulas and how to calculate this?
Thank you so very much!