Circuit principle


Joined Dec 29, 2008
... First glance, it looks like D9 is intended to allow circulation of the inductor current as the circuit is switched off. This is a common method of protecting a relay coil from damage ( the L here ) when power is abruptly terminated.


Joined Mar 14, 2008
It would appear that a periodic voltage is applied to the circuit, v(t), and when this voltage is sufficiently positive, it forward biases D7 and causes the inductor current L to increase based upon the voltage and the L/R time-constant.
When v(t) is below that voltage, D7 no longer conducts and D9 then carries the residual inductor current.
Depending upon the timing of the input voltage and the value of L and the resistors, the current may or may not return to zero before the next positive input.


Joined Mar 2, 2015
what is the principle of operation of this assembly ?
It has no principle of operation, because you haven't told us where you got it, what it's supposed to do or how it's supposed to be used. As it stands it's just a collection of electronic components with no stated purpose.

I refuse to waste my time playing silly guessing games. Give us more information and maybe we can answer your question.