The utility model discloses a switch machine circuit capable of effectively preventing over discharge of a cell and the circuit has a simple structure and low cost. A switch circuit which can automatically disconnect connection of the cell and a load after cell power is reduced to a set value is arranged between the cell and the load. The switch circuit is formed by a transistor, a MOS pipe and a voltage division circuit. Compared to the prior art, by using the circuit of the utility model, the switch circuit which is formed by the transistor, the MOS pipe and the voltage division circuit is additionally arranged between a rechargeable cell used by a small household appliance and the load so that the switch circuit can automatically disconnect the connection of the rechargeable cell and the load when rechargeable cell power is low (a set lower limit value of an electricity storage quantity); the rechargeable cell does not generate a over discharge phenomenon and the rechargeable cell is effectively protected. Simultaneously, the service life is greatly prolonged. The structure is simple. The switch circuit only has a few of components. Product performance is increased and material cost is effectively reduced.