专业英语结课报告专业英语结课报告姓名：张伟 班级：09 电信统本 01 班 学号：091102010123 日期：2012/12/5Summary of the physical electrical knowledge1 circuit1) the formation of the current: the directional movement of the charge formation current. (Directional movement will be the formation of any charge current).2) the current direction: negative flows from the positive power supply.3) Power: provide continuous current (or voltage) of the device.4) power supply is to the other forms of energy into electrical energy. Such as dry cell chemical energy into electrical energy. Generators from mechanical energy into electrical energy.5) continuous current conditions: power supply and the circuit is closed.6) conductor: easy conductive objects called conductors. Such as: metal, the body, the earth, aqueous salt solutions.7) Insulator: the conductive objects called insulators. Such as: glass, ceramics, plastics, oil, such as pure water.8) The circuit is composed of: from the power supply, wires, switches, and electrical appliances.9) Road three states: (1) path: ON circuit called pathway; (2) open: the disconnect circuit called open; (3) short-circuit: direct access to wire circuit called a short circuit on the power poles.10) schematic: schematic symbol indicates that the circuit connection diagram called.11) Series: linking the elements one by one in order, called the series. The (anywhere Disconnect current will disappear).12) in parallel: the components are connected in parallel, and called in parallel. (Each branch is independently of each other). (2) current1) international units: ampere (A); commonly used: milliamperes (mA), the microampere (A), 1 Amps = 103 mA = 106 microamperes.2) measuring the current meter is: ammeter, its use rule is: ammeter connected in series in the circuit; (2) current from the terminal into the “+“ from “-“ terminal; measured current should not exceed ammeter range; absolutely not allowed without the use of electrical appliances and the ammeter connected to the power poles.3) commonly used laboratory ammeter two ranges: 0 to 0 6 Ann, said that the current value of each small cell is 0.02 Ann; the safety of 0 , said that the current value of each small cell 0.1 Ah . 3 Voltage1) the voltage (U): voltage is formed in the circuit current, the power supply is to provide voltage apparatus.2) international units: volts (V); commonly used: kilovolt (KV), millivolts (mV). 1 kV = 103 V = 106 mV.3) measure the voltage meter: voltmeter, usage rules: voltmeter in parallel circuit; (2) current from the “+“ terminal into, from the “-“ terminal; measured voltage not exceeding voltmeter range;4) Laboratory voltmeter two ranges: 0 to 3 volts, the voltage value represented by each small cell is 0.1 volts; 0 15 volts, the voltage value is 0.5 volts per cell represented.5) to memorize the voltage value: dry cell voltage of 1.5 volts; 1-cell lead-acid battery voltage is 2 volts; The family lighting voltage of 220 volts; safe voltage: no more than 36 volts; industrial voltage 380 volts4 Resistor 1) a resistor (R): indicates the role of the conductor on the current obstruction. (Conductor hinder the greater current, then the greater the resistance, and the current through conductor is smaller). 2) international units: ohms (); commonly used: megohms (M), kilohms (K); 1 megohm = 103 kilohms; 3) 1 Kohm = 103333 Europe. 4) determine the the resistor size factor: the material, length, cross sectional area and the temperature (R U and I with its contents). 5) slide rheostat: Principle: changing the length of the resistance wire in the circuit to change the resistance. Effects: by changing the resistance of the access circuit to change the current and voltage in the circuit. Nameplate: a sliding rheostat marked with the “502A“ said the meaning is: maximum resistance of 50, allows the maximum current is 2A. Proper use of: a series in the circuit; b wiring “one last look“; c before energizing the resistance to the greatest place. 5 Ohms law 1) Ohms law: current in a conductor is proportional to the voltage at both ends, with the conductor, with the resistance of the conductor is inversely proportional. 2) the formula: where units: the I Ann (A); U volts (V); the R Europe (). 3) understanding of the formula: in the formula I, U and R must be in the same stretch of the circuit; I, U and R are known in two arbitrary amount can seek another quantity; calculation units must unify. 4) the application of Ohms law: the same resistor is constant, regardless of the current and voltage, and its current is increased with the voltage increases. (R = U / I)(2) When the voltage is constant, the greater the resistance, the current through the smaller. (I = U / R) When the current is constant, the greater the resistance, the greater the voltage across the resistor. (U = IR) 5) resistor series has the following characteristics: (referring to R1, R2 in series, more strings, the greater