We know that BJT transistor can be used as solid-state switches by driving them in either cutoff or saturation mode.
There is some part I do not understand well about fully "ON" state in saturation mode:
My understanding is to drive a transistor in saturation, both BE and CB have to be forward biased, but looking at all the examples provided on the books, say for example 5V input signal, collector supply voltage of 15V, I do not understand how to forward bias the CB junction since Vb is smaller than Vc.
What I can think of is by using a large Rb value, much larger than the Rload connected to the collector side so that the voltage drop on the base is large than the collector in order to forward bias the CB junction.
Books usually just mention to supply maximum Ib in order to get maximum Ic, then the transistor is driven to saturation mode.
Kindly advise on this very very fundamental problems.
Thanks!
There is some part I do not understand well about fully "ON" state in saturation mode:
My understanding is to drive a transistor in saturation, both BE and CB have to be forward biased, but looking at all the examples provided on the books, say for example 5V input signal, collector supply voltage of 15V, I do not understand how to forward bias the CB junction since Vb is smaller than Vc.
What I can think of is by using a large Rb value, much larger than the Rload connected to the collector side so that the voltage drop on the base is large than the collector in order to forward bias the CB junction.
Books usually just mention to supply maximum Ib in order to get maximum Ic, then the transistor is driven to saturation mode.
Kindly advise on this very very fundamental problems.
Thanks!