![](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>)
Measure the resistance with missing meter method, from the positive pole to the resistance RO and then to Rx, ammeter, switch to the negative pole, RX and RO are connected in parallel, and Rx resistance value is calculated with known power supply voltage ro resistance value
Assuming that the internal resistance of the ammeter is zero, the voltage of the power supply is stable
In the first step, only R0 and ammeter are connected to the power supply in series, i1r0 = u, and the voltage value of the power supply is obtained
In the second step, only RX and ammeter are connected to the power supply in series, if i2rx = u, then RX = u / I2
In the circuit as shown in the figure, u = 12 V (and remains unchanged), r = 2 ohm, r = 1 ohm. In order to keep the reading of the ammeter unchanged when the same resistance chain is arbitrarily lengthened or shortened, find: (1) the value of the last resistance RX; (2) the reading of the ammeter at this time
(1) The last resistance chain is shown in the figure: ∵ the reading of the ammeter will remain unchanged when the same resistance chain is arbitrarily lengthened or shortened, ∵ according to r = UI, when the power supply voltage is unchanged, the total resistance in the circuit will remain unchanged; ∵ 1rx = 1R + 12R + Rx, that is, 1rx = 12 Ω + 12 Ω + Rx, we can get: (Rx + 1) 2 = 5, the solution is: RX = - 1 ± 5, ∵ Rx is not 0, let alone negative, ∵ RX = - 1 + 5 ≈ 1.236 A: (1) the value of the last resistance Rx is about 1.236 Ω; (2) the reading of the ammeter is about 9.709a
Connect resistance R and ammeter in series and connect them to a power supply. The current indication is 2 A. when a 3 ohm resistance is connected in series in this circuit, the ammeter indication is reduced to 1.6 A. then the resistance value of resistance R is 12 Ω and the power supply voltage is 24 v
When the resistance R is connected in series with a 3 ohm resistance, the indication of the ammeter will be reduced to 1.6 A, the current will be reduced to 2-1.6 = 0.4 (a), the multiple of the current will be reduced to 2 / 0.4 = 5 (Times), the resistance value of the resistance R will be r = 3 Ω × 5-3 Ω = 12 (Ω), the voltage at both ends of the resistance will be u = RI = 3 × 1.6 = 4.8 (V)
1. The DC circuit in series R = R1 + R2 = 15 ohm, and the current is 1.6A according to I = u / R
12 ohm, low voltage 24 v. The calculated current is 2A according to I = u / R
If it is a pure resistance circuit, set the supply voltage U resistance R U / r = 2A u = 2R U / (R + 3) = 1.6A u = 1.6r + 4.8
It can be concluded that r = 12, u = 24
The power supply voltage is set as u, u △ r = 2A, u △ R + 3 Ω = 1.6A.
It is reduced to: u = 2R, u = 1.6r + 4.8
0.4R＝4.8，R＝12Ω
U＝2R＝24V。
The power of the electric appliance is 800 watts, the working current is 7 A, what is the voltage at both ends?
Because P (electric power, Watt) = I (current, Ampere) * u (voltage, volt), u = P / I = 800 Watt / 7 ampere is about 144.29 volt
The unit of resistance is Ohm. How many megohms is one ohm equal to
1 megohm = 10 ^ 6 ohm. 1 ohm equals 10 ^ - 6 megohm
This is a basic concept, as long as you remember the amount of conversion, you can write it directly
I wish you a better study!
One ohm equals 10 ^ - 6 megohm
One hundred
1 megohm = 1000000 ohm
10 to the - 6th power..
1 ohm = 10 ^ (- 6) megohm
Simple memory: 1 trillion = 1000, 1000 = 1000
1 m Ω = 1000 K Ω = 1000 * 1000 Ω = 10 ^ 6 Ω
What is the actual meaning of one joule
That's what physics says
Using 1n force on the action line of force to make the object travel 1m on the action line of force, the work done is 1J
How to calculate the power of current source,
Is the power of 2A current source absorbed or emitted
5 Ω resistance current = 2A (current source current), direction from right to left, so 5 Ω resistance voltage = 5 × 2 = 10 (V)
KVL: voltage on current source = 5 + 10 + 5 = 20 (V), upper positive and lower negative
The power of current source = 20 × 2 = 40 (W) is emitted
A: the output power of current source is 40W
Actual voltage, actual current: refers to electrical appliances_____ Voltage value or current value during operation
Rated voltage, rated current: refers to electrical appliances_ Normal____ Voltage value or current value during operation
Actual voltage, actual current: refers to electrical appliances__ Actual___ Voltage value or current value during operation
How to read the symbol of Ohm
Oh, MIGA
What is the physical meaning of 1 joule
The work done by a force of 1 Newton on an object is 1 joule if it moves forward for 1 meter
RELATED INFORMATIONS
- 1. If the indication of the ammeter increases by 4 times, R? Ohm resistance should be given Such as the title Better have an explanation
- 2. As shown in the figure, given the resistance R1 = 3 Ω, R2 = 6 Ω, the indication of ammeter A is 0.6A, then the indication of ammeter A1 is 0.6A______ .
- 3. A circuit composed of a resistor, a power supply and an ammeter in series, The indication of the ammeter is 0.12A; if a 10 ohm resistor is connected in series in this circuit, the indication of the ammeter is 0.1A. Calculate the voltage of the power supply and the resistance in the original circuit
- 4. In the circuit shown in the figure, the power supply voltage remains unchanged, R1 = 10 Ω. When the switch S is closed and the slide P of the sliding rheostat is in the middle point, the indication of the ammeter is 0.3A; when the slide P is moved to the rightmost end, the indication of the ammeter is 0.2A. Then the power supply voltage is 0.3A______ 5. The maximum resistance of sliding rheostat is______ Ω．
- 5. If the internal resistance Ra of the ammeter is 0.03 ohm and the internal resistance RV of the voltmeter is 2 kiloohm, the resistance R to be measured is about 1.5 kiloohm, and the internal and external connection methods have small error
- 6. The internal resistances of small range ammeter g, ammeter A and voltmeter V are RG, RA and RV respectively A. RG＜RA＜RVB. RV＜RA＜RGC. RA＜RG＜RVD. RG＞RV＞RA
- 7. The voltage at both ends of a conductor is 12 volts, and the current intensity passing through it is 0.9 amperes, so that the current intensity passing through it is 0.6 amperes, and the voltage applied at both ends of it should be more than 10 amperes
- 8. There is an ammeter with an internal resistance of 1 ohm and a measuring range of 1 A. if you want to expand the measuring range to 5 A, what kind of resistance should be connected? Is it in series or in parallel?
- 9. How many kilowatts of electrical appliances can 4 square millimeter copper wire use
- 10. How many catties of 16 square single strand copper core wire per meter How many jin copper per meter of 16 square single strand copper core wire?
- 11. In the circuit shown in the figure, both ammeter and voltmeter are ideal ammeter. If resistance R1 is open circuit, the following statements are correct () A. The current indicates that the number becomes smaller; B. the voltage indicates that the number becomes larger; C. the power consumed by R3 becomes larger; D. the power consumed by the circuit in the power supply becomes larger
- 12. What can an ammeter measure besides the current?
- 13. What do the poles and zeros of a filter mean
- 14. The physical layer is the foundation of all networks. How many volts are used to represent 1, how many volts are used to represent 0, and how long does a bit last for microseconds?
- 15. What do electric fish and volt battery mean
- 16. In the study of microscopic particles, electron volt (EV) is often used as the unit of energy. 1eV is equal to the kinetic energy of an electron accelerated by 1V voltage. Please deduce the conversion relationship between electron volt and Joule
- 17. In the motor model, the coil resistance is 1 ohm, the voltage at both ends is u = 2 V, and the current in normal operation is 0.8 ampere 1. Electric energy consumed in 1min when small motor works normally 2. The internal energy produced in 1min when the small motor works normally? 3. The mechanical energy produced in 1min when the small motor works normally? 4. Heating power of small motor in normal operation? 5. Total power of small motor in normal operation? 6. Output power of small motor in normal operation?
- 18. When the coil resistance of a motor is 1 ohm, the voltage applied at both ends of the coil is 2V, and the current is 0.8A, the electric energy consumed by the motor in normal operation for one minute is____ J, What is the converted mechanical energy J
- 19. When a motor works normally, the coil voltage is 220V, the coil resistance is 2 ohm, the current is 10a1s, the electric energy consumed is j, and the heat generated in 1min is J
- 20. The resistance of a motor coil is 1 ohm, When the voltage applied at both ends of the coil is 2V, the current is 0.8A, and the motor works normally. Calculate the electric energy consumed by the motor in normal operation for 1min The second question is how much mechanical energy is converted by the motor working for one minute?