# Circuit principle

#### chris_rayan7

Joined Sep 5, 2020
1
what is the principle of operation of this assembly ?

#### drc_567

Joined Dec 29, 2008
1,156
... 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.

#### crutschow

Joined Mar 14, 2008
30,075
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.

#### DickCappels

Joined Aug 21, 2008
8,794
The purpose of the circuit appears to be to test students' ability to analyze circuits like this.

#### MrAl

Joined Jun 17, 2014
9,142
what is the principle of operation of this assembly ?
View attachment 216444
Hi,

What circuits have you done in the past like this one?
You should at least try to give an answer or some thoughts.

#### Picbuster

Joined Dec 2, 2013
1,038
what is the principle of operation of this assembly ?
View attachment 216444
replace the diodes with a wire. what happens?
get them out what happens?
replace D7 by a wire what happens?

hint: look at L and its behavior under a signal ( @ random selected speed, freq , pulse and or polarity).

Picbuster

#### OBW0549

Joined Mar 2, 2015
3,566
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.