Did You Know...
...Daniel Webster invented a "bull plow" to pull out tree stumps. It didn't catch on because it was huge and required four oxen to pull it!
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| Number | Title | Issue Date |
| 7408472 | Device for simulating human activity in an unoccupied dwelling The present invention is a thermally activated electrical switch for use in simulating human activity. The invention is features dual heat sources enclosed in a thermally isolated chamber within the invention. Since the activation of the switch is dependent upon the... | 08/05/2008 |
| 5422808 | Method and apparatus for fail-safe control of at least one electro-mechanical or electro-hydraulic component A fault management apparatus and method are described for a system that includes at least one electro-mechanical or electro-hydraulic component, such as a system valve or main discharge pump in a process plant or water transmission line. An actuator is el... | 06/06/1995 |
| 5210477 | Fan control and diode interlock for electric heaters A fan control board having a central low voltage wiring center as well as a safety interlock for electric heaters. The interlock uses diodes to insure proper fan operation in the event of miswiring of the heater sequencers. Another feature is a quick conn... | 05/11/1993 |
| 4639611 | Bridge circuit system A sensing circuit system including circuitry for sensing impedance variations of a variable impedance element. As disclosed, a bridge circuit system includes a bridge circuit to which the variable impedance element is couplable. The bridge circuit system ... | 01/27/1987 |
| 4320309 | Oscillatory circuit utilizing PTC resistor A control circuit for producing a repetitive closed-circuit, open-circuit condition between an electrical power source, such as a battery, and an electrical load comprises a positive temperature coefficient resistor in series with a relay coil. The PTC re... | 03/16/1982 |
| 4058751 | Light flasher circuit including GTO A lamp is included as a cathode load for a gate-turn-off silicon controlled rectifier (GTO). The conduction path of a transistor is connected between the gate electrode of the GTO and ground. The GTO and lamp are turned off by applying current in the forw... | 11/15/1977 |
