# Derivation of state equations and calculations of transfer impedance.

#### lemon

Joined Jan 28, 2010
125
Hi:
I have this question to complete but don't know what is meant by State Equations. Also it asks for Driving Point. What is that?

Question: In the circuit in Figure Q5-1 write the state equations. Obtain from the state equations the transfer
impedance relating V3 to is and the driving point impedance at the source terminals.

Thank you. Any guidance appreciated.

#### Vahe

Joined Mar 3, 2011
75
For writing state equations, please review my posts in the following message http://forum.allaboutcircuits.com/showthread.php?t=62884

In the circuit that you show, there will be three state equations one for each of the capacitor voltages. You derive the state equation by writing a KCL equation at the top node of each capacitor noting that the capacitor current is C dv/dt where the current is directed in the direction of capacitor voltage drop.

Driving point impedance is the impedance "seen" by the driving source. In this case, I think it refers to the impedance seen from the point of view of the current source.