transforming a switch into a voltage source

[nabliat6]

https://i47.tinypic.com/4pxbte.jpg

i cant understand upon what bais they made such a transition

?

 

[Grossel]

https://i47.tinypic.com/4pxbte.jpg

i cant understand upon what bais they made such a transition

I don't think it's intended to be just another voltage source. I guess it's rather supposed to be a voltmeter.

 

[nabliat6]

no its a voltmeter
its acts like a switch
its a step function of -t

from t>0 and forward it goes to zero like a switch

but how they got its coefficient
??

i cant see how its the same as the original circuit
??