![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
Calculation of maximum power of sliding rheostat by Ohm's law of closed loop If the sliding rheostat is connected in parallel with a resistor, how can the resistor be equivalent to the internal resistance
The equivalent internal resistance is equal to the total resistance of the original resistance and the fixed resistance in parallel
When the resistance of the sliding rheostat is equal to the equivalent internal resistance, the sliding rheostat has the maximum power
Ohm's law formula of whole circuit
I=E/(R+r)
Where e is electromotive force, R is external circuit resistance, R is internal resistance of power supply, internal voltage uine = IR, e = uine + uexternal scope of application: only applicable to pure resistance circuit
What's the difference between Ohm's law of partial circuit and Ohm's law of full circuit? Can you give an example
Use the formula to make it clear:
(1) Ohm's law of partial circuits: I = u / R
U=IR
It is about the voltage drop caused by the resistance R when the current passes through the resistance R in the external circuit of the power supply, or how much current flows through a resistance connected to both ends of the voltage
(2) Ohm's law of the whole circuit: I = E / (R + R0)
E=IR+Ir0
It talks about the potential of the power supply is composed of two parts of voltage drop, one part is the voltage drop ir0 composed of the internal resistance R0 of the power supply, and the other part is the voltage drop IR composed of the external resistance R of the power supply
It can be seen that e is not equal to u. if the voltage drop caused by R0 in the power supply is ignored, then E can be approximately equal to u
How to calculate the voltage in the circuit besides Ohm's law
Junior high school level - = has not talked about power... How can you calculate?
Potential difference between two points, Kirchhoff's law, superposition principle, transformation ratio, power divided by current,
The explanation of Ohm's law of the whole circuit
The more detailed the better
Consider the simplest closed loop. The electromotive force and internal resistance of the power supply are ε and R respectively, and the resistance of the external circuit (or load resistance of the external circuit) is R. from the continuity of the current, we can see that the current passing through each part of the circuit is the same, which is I. suppose the direction of the current is clockwise
RELATED INFORMATIONS
- 1. Nowadays, there are many devices using batteries as power supply, and the amount of batteries used is very large. Some of them are rechargeable batteries, such as battery car batteries and automobile batteries. These rechargeable batteries all have one feature: the newly purchased batteries can be used for a long time after charging. After long-term use, they will be fully charged, and the power will soon run out. Please use Ohm's law of the whole circuit for analysis! Thank you for your explanation!
- 2. The trajectory of a point whose distance from the plane to the fixed point O is equal to 2cm is ()
- 3. There are two fixed points a and B in the plane, and | ab | = 2. The ratio of the distance between a moving point m and two points a and B in the plane is 2:1
- 4. Two fixed points a (- C, 0), B (C, 0). The sum of the distances from the moving point P to the two fixed points is a constant 2A. Find the trajectory equation of point P
- 5. Given that the distance from the moving point P to the fixed point F (3,0) and to the fixed value line x = 5 / 2 is constant 2 √ 3 / 3, the trajectory equation of point P is obtained Urgent``
- 6. In the space rectangular coordinate system, the point a (1,0,2) B (1, - 3, - 1) m is on the Y axis, and the distance to a and B is equal In the space rectangular coordinate system, if the point a (1,0,2) B (1, - 3, - 1) m is on the Y axis and the distances to a and B are equal, then the coordinate of M is?
- 7. In Cartesian coordinates, the distance OP from point P (- 2,3) to the origin=______ ．
- 8. In Cartesian coordinates, the distance from the point P (- 1, (√ 3) / 2) to the origin o is
- 9. The projection of a point on the coordinate axis of the space coordinate system How to find. Can give an example to illustrate, as long as I can understand. Success can be + points How to find it when drawing
- 10. The eccentricity of ellipse e: x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 (a > b > 0) is e, P is the point on e, from P to the circle x ^ 2 + y ^ 2 = B ^ 2, make tangent PA and Pb, a and B are tangent points, Ask if there is a point P, so that PA ⊥ Pb? If there is, calculate the point P coordinate; if not, explain the reason
- 11. Ohm's law of closed circuit Is the terminal voltage necessarily the power supply voltage? What are the internal resistance and external resistance? What are their differences and connections?
- 12. Ohm's law in closed circuit U = E / R / R + I (to explain, u is the road voltage, e is the power electromotive force, e is the numerator, R / R + I is the denominator, R / R + I means the quotient of R divided by R plus I). How did this formula come out? Thank you!
- 13. As shown in the figure, line a is the U-I diagram line of a power supply, and line B is the U-I diagram line of resistance R. when the power supply and the resistance are used to form a closed circuit, the output power and internal resistance of the power supply are () A. 4W，1ΩB. 6W，1ΩC. 4W，0.5ΩD. 2W，0.5Ω
- 14. The variation law of the terminal voltage U of a power supply with the resistance R of the external circuit is shown in figure (a), and the straight line of u = 12V in the figure is the asymptote of the line. Now, the power supply and a rheostat R0 are connected into the circuit as shown in Figure (b). It is known that the maximum allowable current of the power supply is 2a, and the maximum resistance of the rheostat R0 = 22 Ω (1) The results are as follows: (1) the electromotive force E and internal resistance R; (2) the output voltage range of a and B at no load; (3) the minimum resistance of a and B that can be connected to load
- 15. Ohm's law There are 6V 3W and 3V 1W bulbs, which are connected in series in a 9V circuit. In this paper, which bulb is connected with a resistor in parallel can make both lamps light normally. Why?
- 16. 1. The voltage at both ends of the circuit is 6 V, the resistance of R1 is 8 Ω, and the current through L1 is 0.2A Solution: 1. Current through L2. 2. Voltage at both ends of L1. 3. Voltage at both ends of L2. 4. Resistance of L2 2. R1 and R2 are connected in series in a circuit with a voltage of 6 v. the current passing through the resistor R1 is 0.2 a, R2 = 10 Ω, and the resistance of R1 is calculated The first question is series connection
- 17. To measure the resistance of a resistance, according to the deformation formula of Ohm's Law (), just use () to measure To measure the resistance value of a resistance, according to the deformation formula of Ohm's Law (), as long as you use () to measure the voltage at both ends of the resistance () and () to measure the current through the resistance, you can calculate the resistance value. This method of measuring resistance is called ()
- 18. Use resistance, sliding rheostat, power supply and ammeter to measure rated power of bulb The resistance is known
- 19. When using volt ampere method to measure resistance, it is found that the voltmeter and ammeter have small indication after closing the switch. What is the reason that the bulb is not on To see clearly, the ammeter and voltmeter have small indication and the bulb is not bright. The original title is written like this
- 20. I want to ask a question: if in the experiment, the corresponding current value and voltage value have been given, the resistance value can be obtained by Ohm's law If the results are very different each time, what may be the reason? For example, why are the results different when using a fixed circuit diagram to measure the resistance of the same small lamp? The reason why the resistance value changes is that it is always on for measurement. Does the resistance have a certain temperature? Thank you for your reply