! >:Jiangdu Dinghu Middle School (225266) 扈家连 sliding varistor is the circuit connecting the physical circuit of junior high school, close the switch, adjust the sliding piece of the sliding varistor, so that the voltage at both ends of the fixed value resistance changes in an integral multiple, record the corresponding The current value, and the analysis, concludes that the current through the conductor is proportional to the voltage applied across it.
In the "relationship between current and resistance", when the earth is at position A, if the surface OP is zero-degree warp, it is also called the prime meridian, and the prime meridian plane passes through the center of the sun. When the earth reaches the B position, the prime meridian just turns 2tt, that is, the satellite rotates once a week. When the earth reaches the C position, the OP prime meridian and the sun center are in the same plane again, that is, the sun is “positive†again, from the point P. At noon, so the earth is from day A to C for one day. From position A to time B is less than A to C time, that is, B. The exercise time is calculated as follows.
The orbit of the orbit is approximately a circle, and the angle of rotation of the earth is 0 = + one for the earth's rotation time, and T for the year when the U is = 7 amount, P is the amount of P, and the small bulb emits light normally. < 2. In experiments such as "volt-ampere measurement resistance", "measurement of small bulb power", "research electromagnet", "installation of DC motor model", etc., in order to prevent excessive current in the circuit, burn the electric meter or electric appliance In the circuit, the sliding varistor is connected in series, and the sliding piece of the sliding varistor should be placed at the position with the largest resistance value before the closing switch is turned on, thereby limiting the current and protecting the circuit.
In some electrical calculation problems, the sliding varistor is often used as a fixed value resistor, and the nameplate has the word "xnxa". For example, 2n1A means that the resistance of the varistor varies by 020D, and the maximum current allowed to pass is 1A. In some design experiments, the sliding varistor is often used as a fixed value resistor. For example, in the experiment of "volt-amperometric resistance", if the ammeter is broken, there is "XflxA" on the sliding varistor, how to use the remaining The equipment measures the resistance of the resistance to be tested, which is a circuit designed by a student for this purpose. Please think about and answer the following questions: 1 Briefly describe the main steps and experimental principles of the experiment; 2 Write a mathematical expression for calculating the resistance of the resistance ruler to be tested.
It is worth noting that although the sliding varistor has different functions in the experiment, its essential characteristics are the same, that is, by changing the length of the resistance wire in the connected circuit to change the resistance, thereby changing the voltage across the circuit and the circuit. Current. This is determined by the way the sliding varistor is connected to the circuit, because in the junior high school electrical experiment, the sliding varistor is usually connected in series in the circuit, and the power supply voltage is generally considered to be constant, so its "variable resistance" changes the current in the circuit. Its "dividing voltage" changes the voltage across the other parts of the circuit. Voltage is the cause of the current. Therefore, for some circuits of the series circuit, the voltage across it changes, and the current through it changes at the same time. The sliding varistor actually plays the "double" effect of simultaneously changing the voltage across the circuit and the current passing through it. .
Furniture Chair,Student Study Chair,Table And Chair Set,Adjustable School Table And Chair
AU-PINY FURNITURE CO., LTD , https://www.jmaupiny.com