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How does the change of resistance of sliding rheostat affect the change of voltage This is the eighth edition of Zhejiang Education Press. May I ask why the voltage of sliding rheostat in the circuit (series or parallel) changes? Why does the resistance of constant value resistor not change but affect the voltage? Does sliding rheostat affect the current, resistance and voltage? Another question: which factors are related to the brightness of the bulb? Current, voltage or resistance? There must be a lot of additional points!
In series and parallel circuits, the resistance of sliding rheostat changes
In a series circuit, the ratio of voltage is equal to the ratio of resistance
In parallel circuit, the ratio of current is equal to the inverse ratio of resistance
So in the circuit, when the resistance value of the sliding rheostat (connected to the circuit) changes, it causes the change of voltage or current. In the experiment, the resistance value of the constant value resistor (the characteristic of the constant value resistor) changes the voltage or current at its two ends
The change of resistance value of sliding rheostat will affect the voltage and current distribution of the whole circuit, but it is conditional
For example: in a series circuit, the resistance value of the sliding rheostat increases and the total resistance increases. Because the power supply voltage remains unchanged, the total current decreases. Because the voltage at both ends of the sliding rheostat and the constant value resistor is equal to the power supply voltage, and the ratio of the voltage at both ends of the sliding rheostat and the constant value resistor is proportional to the resistance, the voltage at both ends of the sliding rheostat increases and the voltage at both ends of the constant value resistor decreases
If it is in parallel circuit, the resistance value of sliding rheostat will increase, which will increase the total resistance. Because the power supply voltage remains unchanged, the main circuit current will decrease. In the branch circuit of sliding rheostat, because the voltage remains unchanged (still the power supply voltage), but the resistance will increase, so the current will decrease
Resistance is related to the composition of materials. Gold and silver have the lowest resistivity and can be used to conduct electricity. However, considering economic factors, the resistivity of copper is slightly higher than that of them, but most wires are made of copper wire. This is a property of objects. There are also some insulators with high resistance, some semiconductors and superconductors. In fact, these are all related to the properties of materials, The title says: "constant resistance" means: the resistance has not changed
Why does the voltage decrease with the increase of electric power in parallel circuit?
Daily home lighting circuit voltage is 220 V, often in the hot summer, due to large-scale air conditioning and other high-power electrical appliances, the voltage is often less than 220 v. so what is the specific reason for this phenomenon?
In real life, the voltage at both ends of electrical appliances is lower than 220 V, because there is a resistance on the transmission line. The resistance of wire is connected in series with electrical appliances to share part of the voltage. Electrical appliances are connected in parallel, and the more electrical appliances are used, the smaller the resistance is. More electrical appliances are used, the smaller the parallel resistance of electrical appliances is, and the voltage is shared by wire resistance in series, According to Ohm's law, when the voltage on the wire is high, the voltage of the appliance is low
In the circuit shown in the figure, the resistance R1 = 4 Ω, R2 = 6 Ω, and the resistance in the power supply R = 0.6 Ω. If the total power consumed by the power supply is 40W, and the output power of the power supply is 37.6w, calculate the electromotive force of the power supply and the resistance of the resistance R3
The power consumed by the internal resistance of the power supply is I2R = ptotal - ptotal: I = 2A & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; from ptotal = EI & nbsp; & nbsp; the total resistance of the external circuit is r = r1r2r1 + R2 + R3 & nbsp; & nbsp; from Ohm's law of closed circuit E = I (R + R) & nbsp
RELATED INFORMATIONS
- 1. If the voltage U and the resistance R are doubled simultaneously in a circuit, how will the power change? P = the square of (2U) divided by 2R Why is the square of (2R) divided by R
- 2. In the experiment of exploring the relationship between current and voltage, resistance, when exploring the relationship between current and resistance, we should () A. Adjust the sliding rheostat to keep the current in the circuit constant B. Adjust the sliding rheostat so that the voltage at both ends of different fixed resistor R remains unchanged C. Make the voltage at both ends of resistance R change in multiple D. The current in the circuit should be changed in multiple during each measurement
- 3. In the experiment of studying the relationship between current, voltage and resistance, what is used to control the current in the circuit
- 4. Is the statement "when the resistance of a conductor is constant, the current is proportional to the voltage"? Those who are right should pay attention! I thought it was right, but the answer is wrong! I wonder if it should be said that when the resistance of a conductor is constant, the current in the conductor is proportional to the voltage at both ends of the conductor! I want to win your opinions,
- 5. The resistance of a conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to the current passing through the conductor Why wrong? How to understand the relationship between resistance, voltage and current? Don't use books. It's suitable for multiple choice questions
- 6. When exploring the relationship between the current on the resistance and the voltage at both ends, what should be kept unchanged?
- 7. The specification of an electric iron is "220 V & nbsp; & nbsp; & nbsp; 110 W". Please answer the following questions: (1) what is the normal working current of the electric iron? (2) What is the resistance of the electric iron? (3) How much heat does it produce when it is electrified for 10 minutes at rated voltage?
- 8. In order to explore the relationship between current and resistance, Xiao Ming replaced the 10 ohm resistance between a and B with 20 ohm resistance as shown in Figure 8. After closing the switch, the next operation should be () A. Record the indication of ammeter and voltmeter B. Move the sliding rheostat to the right C. Move the sliding rheostat to the left D. Increase the number of batteries appropriately B, why.
- 9. As shown in the figure, the light bulb L is marked with "6V 3W", and the power supply voltage remains unchanged. When the switch is closed, the resistance of the sliding rheostat connected to the circuit is 4 Ω, and l lights normally, the power supply voltage is 0_____ 5. If the total power consumed by the circuit is 3.2w by changing the position of slide plate P of the sliding rheostat, then the actual power of the small bulb is___ W A graph is a series
- 10. In the circuit shown in the figure, the power supply voltage remains unchanged. There may be faults in resistance R and lamp L. before and after the key s is closed, the position of ammeter pointer remains unchanged. The correct judgment in the following is () A. If lamp L does not light up, only resistance R is short circuited. B. If lamp L does not light up, only resistance R is open circuited. C. If lamp L lights up, only resistance R is short circuited. D. if lamp L lights up, only resistance R is open circuited
- 11. How to change resistance current and voltage with sliding rheostat in series circuit? How to change resistance current and voltage with sliding rheostat in parallel circuit
- 12. How to change resistance, current and voltage in series / parallel circuit? The sliding rheostat changes the resistance in the circuit. How do the current and voltage at both ends of the planting resistor change? How do the total voltage and current change?
- 13. When a resistance is increased by 3 Ω, the current in the circuit becomes four fifths of the original value. If the supply voltage remains unchanged, what is the original value of the resistance?
- 14. It is known that the circuit has two fixed value resistors, a switch and a 60V power supply connected by wires. And the power supply voltage is constant. When the switch is in a certain state (open or closed), the electric power of the circuit is 40W. When the switch is in another state, the electric power of the circuit is increased by 20W. The resistance values of the two fixed value resistors are calculated
- 15. Why can't we screw copper and aluminum wires together to connect the lines
- 16. How to prevent oxidation of wire joint, copper wire and aluminum wire joint
- 17. (1) If the wire connection in the home circuit is not in good contact, it will often heat there and cause danger. Why 2. Xiao Li bought two incandescent bulbs, one marked with "20V 100W" and the other marked with "220V 15W". Can you judge which bulb to compete with 3. In order to save electricity, Xiao Hui wants to use two "220V 15W" light bulbs in series, and then connect them to the 220 V home circuit, and use them as aisle lights. Do you think this method is feasible? Can two light bulbs replace one light bulb really save electricity? Calculate the actual electric power of each light bulb in series 4. The working resistance of a refrigerator in Xiao Li's home is 20 ohm, and the working current is 0.5A. Can you estimate the electric power of this refrigerator
- 18. When 3V voltage is applied at both ends of a conductor, the current passing through the conductor is 0.2A, and the resistance of the conductor is______ When a voltage of 6V is applied at both ends of the conductor, the resistance of the conductor is equal to______ Ω．
- 19. In the circuit as shown in the figure, the power supply voltage is 6V constant, the range of ammeter is 0-0.6a, the range of voltmeter is 0-3v, the lamp L1 and The specifications of L2 are "6V, 1.8W" and "6V, 1.2W" respectively. The specifications of sliding rheostat are "50ohm, 1.5A". Only close S1S2 to find the range of ammeter and voltmeter (the safety of components in the circuit)
- 20. In the experiment of exploring the relationship between current and resistance, the slide of sliding rheostat is adjusted to keep the voltage at both ends of the resistance unchanged. If the voltage does not change, does not the current also change? Does not the calculated resistance also change?