End effector with detectable configurations

1. A surgical instrument, comprising:

an end effector, comprising:

a first jaw comprising a first electrode;

a second jaw, wherein at least one of the first jaw and the second jaw is movable relative to the other one of the first jaw and the second jaw to transition the end effector between an open configuration, an approximated configuration, and a fully approximated configuration, and wherein the second jaw comprises:

a second electrode, wherein tissue is captured between the first electrode and the second electrode in the approximated configuration; and

at least one spacer extending from the second electrode, wherein the at least one spacer is configured to maintain a minimum predetermined distance between the first electrode and the second electrode when the end effector is in the fully approximated configuration, and wherein the at least one spacer is simultaneously in contact with the first electrode and the second electrode in the fully approximated configuration;

a switch configured to control energy transmission between the first electrode and the second electrode, wherein the switch is activatable to permit energy transmission between the first electrode and the second electrode; and

a circuit configured to:

detect activation of the switch;

detect an impedance between the first electrode and the second electrode in response to the activation of the switch;

generate a first response corresponding to the open configuration of the end effector when the impedance is greater than or equal to a predetermined threshold;

generate a second response corresponding to the approximated configuration of the end effector when the impedance is in a first range of impedance; and

generate a third response corresponding to the fully approximated configuration when the impedance is in a second range of impedance different from the first range of impedance.

2. The surgical instrument of claim 1 , wherein the second range of impedance is defined by an impedance of the at least one spacer.

3. The surgical instrument of claim 1 , wherein the at least one spacer comprises a semi-conductive material.

4. The surgical instrument of claim 1 , wherein the second range of impedance is selected from a range of about 500 ohms to about 2000 ohms.

5. The surgical instrument of claim 1 , wherein the first range of impedance is defined by an impedance of the tissue.

6. The surgical instrument of claim 1 , wherein the first range of impedance is selected from a range of about 3 ohms to about 400 ohms.

7. The surgical instrument of claim 1 , wherein the circuit comprises a finite state machine configured to:

detect the activation of the switch;

detect the impedance between the first electrode and the second electrode in response to the activation of the switch;

generate the first response corresponding to the open configuration of the end effector when the impedance is greater than or equal to the predetermined threshold;

generate the second response corresponding to the approximated configuration of the end effector when the impedance is in the first range of impedance; and

generate the third response corresponding to the fully approximated configuration when the impedance is in the second range of impedance.

8. The surgical instrument of claim 1 , wherein the circuit comprises:

a processor; and

a memory that stores program instructions, which when executed from the memory cause the processor to:

detect the activation of the switch;

detect the impedance between the first electrode and the second electrode in response to the activation of the switch;

generate the first response corresponding to the open configuration of the end effector when the impedance is greater than or equal to the predetermined threshold;

generate the second response corresponding to the approximated configuration of the end effector when the impedance is in the first range of impedance; and

generate the third response corresponding to the fully approximated configuration when the impedance is in the second range of impedance.

9. The surgical instrument of claim 8 , wherein the circuit comprises a finite state machine, wherein the finite state machine comprises at least one combinational logic circuit configured to cause the finite state machine to:

detect the activation of the switch;

detect the impedance between the first electrode and the second electrode in response to the activation of the switch;

generate the first response corresponding to the open configuration of the end effector when the impedance is greater than or equal to the predetermined threshold;

generate the second response corresponding to the approximated configuration of the end effector when the impedance is in the first range of impedance; and

generate the third response corresponding to the fully approximated configuration when the impedance is in the second range of impedance.

10. The surgical instrument of claim 8 , wherein the circuit comprises a finite state machine, wherein the finite state machine comprises at least one sequential logic circuit coupled to at least one memory circuit, the at least one memory circuit configured to store a current state of the finite state machine, wherein the sequential logic circuit is configured to cause the finite state machine to:

detect the activation of the switch;

detect the impedance between the first electrode and the second electrode in response to the activation of the switch;

generate the first response corresponding to the open configuration of the end effector when the impedance is greater than or equal to the predetermined threshold;

generate the second response corresponding to the approximated configuration of the end effector when the impedance is in the first range of impedance; and

generate the third response corresponding to the fully approximated configuration when the impedance is in the second range of impedance.

11. The surgical instrument of claim 10 , wherein the sequential logic circuit is either synchronous or asynchronous.