As shown on this slide, modern gas cook tops control the heat level electrically rather than manually. The valve control unit will be similar to the picture in the upper right. It can be seen that in addition to the on/off valve of the whole unit, there are separate controls for the four individual burners. A stepper motor is used adjust the gas flow for each burner. The safety valve is simply an on or off type of control that does not need to be controlled by the precision of a stepper motor. If a sensor detects a potential danger, it turns off the gas supply to all burners using this motor. To drive the safety valve motor, a forward/reverse brush motor driver like the LB1848MC and LB1973JA can be used. Gas cook tops run the motors and driver by an internal battery, since a gas stove does not require electricity to work. Because of this the design will call for a motor driver IC which has low current consumption and can be driven from a low voltage source.