Patent ID: 7262950

Claim:
A relay device comprising: a power supply circuit for supplying a constant voltage; a relay unit having a coil for opening/closing a contact point; a driver transistor connected in series with the power supply circuit and the coil; and a control circuit for controlling the driver transistor to control a current supply to the coil, wherein the control circuit is constructed to turn on the driver transistor to apply the constant voltage to the coil to start a contact point operation of the contact point, wherein the control circuit has a holding current stabilizing and limiting circuit for controlling a holding current as a supply current to the coil of the relay unit after the contact point operation based on the constant voltage to the coil is completed so that the holding current is kept to a predetermined constant value, which is smaller in value than an operating current, which flows as the supply current to the coil when the contact point operation is being carried out by the constant voltage, and is larger than a minimum holding current value, which is necessary to hold a contact point state after the contact point operation, and wherein the control circuit has a refreshing circuit for periodically supplying the constant voltage to the coil in place of the holding current while the holding current is supplied to the coil.