eblc1388
Active Member
He said it does not conduct when the BE voltage is less than 0.54V and conducts when it is higher. This is how the circuit regulates its current.eemage21 said:Also - you were wrong in stating that the transistor on the left is not conducting - it is.
Now referring to what's you have said earlier:
eemage21 said:Regarding LM317's - as long as you pick the right ratio for your resistors, and keep your input voltage above 1.25V above your output voltage (in yourcase you need to make sure your input doesn't go below 4.25V if you want 3V output), then you will be fine.
I have checked. The input voltage needed to maintain regulation is at least 1.5V at output of 20mA and more than 2.0V at 1 A, according to the LM317 datasheet. So one would need at least 5V for a 3V output. Please quote any reference to your above comment of the 1.25V higher input voltage requirement.