When the power supply is connected to the circuit, the potential difference between the two ends of the power supply is equal to, less than and greater than the electromotive force of the power supply Such as the title

When the power supply is connected to the circuit, the potential difference between the two ends of the power supply is equal to, less than and greater than the electromotive force of the power supply Such as the title

When no-load, the potential difference between the two ends of the power supply is equal to the electromotive force
Under load (the current flows out from the positive electrode), the potential difference between the two ends of the power supply is less than the electromotive force
When charging (the current flows in from the positive electrode), the potential difference between the two ends of the power supply is greater than the electromotive force

Why is the electromotive force of the power supply equal to the sum of the voltages of the internal and external circuits,
When the positive charge is moved from the negative to the positive inside the power supply, the non electrostatic force does work. Why does the electric potential energy increase? But the internal electrostatic force also does work. It is negative work, and the electric potential energy also increases. How can this be explained?

A:
(1) Why is the electromotive force of the power supply equal to the sum of the voltages of the internal and external circuits -- energy conservation? The internal non electrostatic force of the power supply does work and converts other forms of energy into electric energy. Electric energy is consumed in two parts: first, in the internal circuit, the electric energy is converted into internal energy by doing work through the electric field force; second, in the external circuit, the electric energy is converted into other forms of energy by doing work through the electric field force
So w is not = w outside + W inside, EQ = UQ + U inside Q, e = u + U inside = u + IR, if the outside circuit is pure resistance, u = IR, e = I (R + R)
(2) When the positive charge is moved from the negative to the positive inside the power supply, the non electrostatic force does work. Why does the electric potential energy increase? But the internal electrostatic force also does work. It is negative work, and the electric potential energy also increases. How can this be explained?
When the positive charge is moved from the negative to the positive in the power supply, the non electrostatic force does the positive work, the electrostatic force does the negative work, and the electrostatic force does the negative work. The electric potential energy increases (the work done by the electric field force is equal to the opposite number of the change of the electric potential energy). Only the work done by the electric field force (the electric field force of the electrostatic field, also known as the electrostatic force) can change the electric potential energy of the object, while the work done by the non electrostatic force can transform other forms of energy into electric energy