Variable resistance means

The invention provides a variable resistance device comprising a first connection pin, a second connection pin, a resistance regulating branch circuit and a resistance display branch circuit. The first connection pin and the second connection pin are used for connecting with external circuits; the resistance regulating branch circuit is connected between the first connection pin and the second connection pin and supplies regulating resistance for the external circuits; the resistance display branch circuit is used for displaying the resistance value of the resistance regulating branch circuit. The variable resistance device is capable of regulating the resistance of a circuit board conveniently.