초록 ▼

An electronic disconnect circuit protects an electronic device, such as a radio, installed in a motor vehicle from overvoltage condition in which the normal internal protection is inadequate. A normally closed relay includes 2 sets of terminals connected in the ground conductor and in the voltage co

An electronic disconnect circuit protects an electronic device, such as a radio, installed in a motor vehicle from overvoltage condition in which the normal internal protection is inadequate. A normally closed relay includes 2 sets of terminals connected in the ground conductor and in the voltage conductor of the power cable connected to the electronic device. The relay coil is connected through a diode which becomes conductive if the voltage in the ground conductor rises above the voltage in the other conductor, thus protecting the radio or similar electronic device from a reversal of polarity as would occur when a battery charger or similar device is improperly connected to the vehicle. A switching transistor responds to an over voltage condition to turn on the relay coil when an over voltage condition occurs, such as during a high voltage jump start or a high voltage transient condition.

대표청구항 ▼

[ What is claimed is:] [1.] In a vehicle having an electrical system including an electrically conductive body normally providing a ground signal and a source of electrical energy normally providing a positive voltage signal and electronic equipment a circuit connecting said electronic equipment to

[ What is claimed is:] [1.] In a vehicle having an electrical system including an electrically conductive body normally providing a ground signal and a source of electrical energy normally providing a positive voltage signal and electronic equipment a circuit connecting said electronic equipment to both said energy source and to said vehicle body, said circuit including an electronic disconnect component responsive to a reversal of polarity of the vehicle electrical system in which the vehicle body becomes positively charged relative to said positive voltage signal for disconnecting the electronic equipment from both said energy source and said vehicle body.