The two capacitor paradox or capacitor paradox is a paradox, or counterintuitive thought experiment, in electric circuit theory. The thought experiment is usually described as follows: Two identical capacitors are connected in parallel with an open switch between them. One of the capacitors is charged with a voltage of This problem has been discussed in electronics literature at least as far back as 1955. Unlike some other paradoxes in science, this paradox is not due to the underlying physics, but to the limitations of the 'ideal circuit'. There are several alternate versions of the paradox. One is the original circuit with the two capacitors initially charged with equal and opposite voltages $${displaystyle +V_{i}}$$ and $${displaystyle -V_{i}}$$. Another equivalent version is a single charged capacitor •.