Patents by Inventor Lester C. Liu

Lester C. Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Increasing temperature warning device
    Patent number: 4901060
    Abstract: An increasing temperature warning device for protecting an item from high temperature or fire damage comprising a thyristor connected in parallel with a reference voltage source. An audible or visual warning means is connected in series with the thyristor. When the temperature of the thyristor exceeds a specified temperature, the thyristor switches on and the warning means is activated. A series combination of a diode and a resistor can be connected in parallel with the gate of the thyristor to cause the reference voltage to be a function of the ambient temperature of the protected device. A diode connected in series with the thyristor allows the increasing temperature warning device to be powered by an alternating current source and a pair of thin wire fuses protect the warning device from excess current situations.
    Type: Grant
    Filed: October 11, 1988
    Date of Patent: February 13, 1990
    Inventor: Lester C. Liu