Circuits II EE221 Unit 8 Instructor: Kevin D. Donohue. 2 Port Networks –Impedance/Admittance, Transmission, and Hybird Parameters. 2-Port Circuits.
2 Port Networks –Impedance/Admittance, Transmission, and Hybird Parameters
Show that Voc=8 V, Isc = 0.08 A, and Rth = 100
Now take away the source from the previous example:
If the circuit is linear, then a general linear relationship between the terminal voltages and currents can be expressed as:
Determine the inverse transmission parameter model for the given circuit.
Show that a =18/5, b= 100, c = 7/250 Siemens, d= 1.
If inverse transmission parameters are known, then the following circuit can be used as an equivalent circuit:
This circuit is helpful when implementing in SPICE withoutknowledge or details of circuit from which parameterswere derived.
By strategically selecting the constraints on port variables, the two-port parameters are the ratios of other port variables. Therefore:
Example: Determine the SPICE commands to find the abcd parameters for the circuit below.
1) Consider setting v1=0, then
2) Excite the circuit with i2=1 then
3) Use SPICE to compute v2 and i1 to solve for b andd.
4) Consider setting i1=0, then
5) Excite the circuit with v2=1, then
6) Use SPICE compute v1 and i2 to solve for a and c.
Inverse Hybrid Parameters