![]() ![]() The city councilmen and their backers are desperate to defeat the people's Town Center Initiative through their reprehensible action. Their meaningless and deceptive measure serves only one purpose: To confuse voters ! If it passes with more votes than the 2015 Town Center Initiative it will cancel the voters initiative. It is the equivalent of a "NO" vote on the Citizens' Town Center Initiative. The council's measure is a deceptive smokescreen. That amendment was approved into law by the Council in September, 2015 but does not even have the required California Coastal Commission approval. Their measure changes no laws currently in effect and offers no indication of how they intend to develop Town Center other than their amendment to drastically reduce the parking requirements for new developments. It is common to provide 4-wire connections to current-sensing shunt resistors of low resistance operating at high current.Over the strenuous objections of Residents at the February 2 city council meeting, the councilmen voted to put a measure opposing the 2015 Town Center Initiative on the June 7th ballot. The technique is commonly used in low-voltage power supplies, where it is called remote sensing, to measure the voltage delivered to the load independent of the voltage drop in the supply wires. The force wires may have to carry a large current when measuring very small resistances, and must be of adequate gauge the sense wires can be of a small gauge. If the force and sense connections are exchanged, accuracy can be affected, because more of the lead resistance is included in the measurement. It is usual to arrange the sense wires as the inside pair, while the force wires are the outside pair. Since almost no current flows to the measuring instrument, the voltage drop in the sense leads is negligible. A pair of sense connections (voltage leads) are made immediately adjacent to the target impedance, so that they do not include the voltage drop in the force leads or contacts. These generate a voltage drop across the impedance to be measured according to Ohm's law V= IR. When a Kelvin connection is used, current is supplied via a pair of force connections (current leads). ![]() A clip, often a crocodile clip, that connects a force-and-sense pair (typically one to each jaw) is called a Kelvin clip. A pair of contacts that is designed to connect a force-and-sense pair to a single terminal or lead simultaneously is called a Kelvin contact. Each two-wire connection can be called a Kelvin connection. įour-terminal sensing is also known as Kelvin sensing, after William Thomson, Lord Kelvin, who invented the Kelvin bridge in 1861 to measure very low resistances using four-terminal sensing. For example, an LCR bridge instruction manual recommends the four-terminal technique for accurate measurement of resistance below 100 ohms. This is an advantage for precise measurement of low resistance values. Separation of current and voltage electrodes eliminates the lead and contact resistance from the measurement. Four-point probes are also used to measure sheet resistance of thin films (particularly semiconductor thin films). Four-terminal sensing is used in some ohmmeters and impedance analyzers, and in wiring for strain gauges and resistance thermometers. ![]() In electrical engineering, four-terminal sensing ( 4T sensing), 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements than the simpler and more usual two-terminal (2T) sensing. Current is supplied via force connections 1 and 4. Four-point measurement of resistance between voltage sense connections 2 and 3. ![]()
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