Did You Know...
...In 1790, the cost to obtain a patent was between $4 and $5.
PatentStorm News
Make the Most of Our Site
See this month's Top Inventors and Most Cited Patents.
Stay on top of the latest innovations by subscribing to an RSS feed.
Registered users: Manage your profile.
| Number | Title | Issue Date |
| 5172007 | Corrosion inhibiting switched polarity fuel level sender module Galvanic corrosion of the fuel sender immersed in the corrosive fuel mixture is minimized by supplying the sender with current that periodically switches polarity. The switching rate is selected to prevent or greatly minimize irreversible oxidation buildu... | 12/15/1992 |
| 5055758 | Smart fuel pump controller The motor drive circuit has an instrumentation amplifier with a programmable gain set by selectively blowing fuses during initial circuit calibration. The quasi-sawtooth waveform of a relaxation oscillator is compared with the amplified and conditioned si... | 10/08/1991 |
| 5050433 | Electronic circuit for fuel level sensor Corrosion of the fuel tank float device by electrolysis is minimized by driving the fuel level sender with short duty cycle pulses instead of a continuous current. While the fuel level sender is energized by a pulse, the analog sample and hold circuit obt... | 09/24/1991 |
| 4941348 | Electromotive sensor The circuit senses abrupt change in motion of an electromotively-driven part such as the onset of valve seating in a solenoid-operated valve. A constant current source supplies power to the solenoid coil and a pulse detector circuit monitors the voltage a... | 07/17/1990 |
| 4897632 | Power door lock interlock circuit The power door lock interlock circuit senses the presence of an ignition key in the ignition and also senses when a door is open. When these conditions are met, the power door lock is placed in an interlock condition whereby pressing the power door lock b... | 01/30/1990 |
| 4884215 | Airflow sensor and control circuit The airflow sensor uses a flow sensing bridge having a thermal element which senses airflow as a function of electrical energy applied to the bridge. Energy is applied to the bridge to maintain the thermal element at a constant temperature and constant re... | 11/28/1989 |
| 4789851 | Power door lock interlock circuit The power door lock interlock circuit senses the presence of an ignition key in the ignition and also senses when a door is open. When these conditions are met, the power door lock is placed in an interlock condition whereby pressing the power door lock b... | 12/06/1988 |
| 4674115 | Programmable telephone switcher The programmable telephone screening device routes an incoming call to a selected telephone device, depending on preestablished device priorities and upon access codes dialed by the caller. The device provides call hold, call forwarding and automatic dial... | 06/16/1987 |
