Example 1:
(1) First contact AB together, and then put the positively charged C close to B (close to either of them is ok, here the analysis is close to B), then there are positive in A and negative in B.
(2) Then separate AB and remove C.
(3) Ground B so that B is not charged.
(4) Finally, the positively charged A is in contact with the uncharged B. After stabilization, A and B have the same amount (because AB has the same shape).
Example 2:
(1) First contact AB together, and then put the positively charged C close to B (close to either of them is ok, here the analysis is close to B), then have A positive charge on A, and have A negative charge on B.
(2) Then separate AB and remove C.
(3) Ground A, so that A is not charged.
(4) Finally, the uncharged A is in contact with the negatively charged B. After stabilization, A and B have the same amount (because AB has the same shape).
Example 3:
(1) First contact AB together, and then bring the positively charged C close to A, then there is A negative charge on A and A positive charge on B.
(2) Then separate AB and remove C. A can be negatively charged and B can be positively charged by the same amount.