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When a wire passes the current of 0.5A for 10s, the amount of charge passing through the wire is
5 Coulomb
If a 5V USB interface is connected to a 3V led, how much resistance should it be
If there are two LED lights, how much resistance do you need
Is it possible to connect several lights without resistance?
The maximum output current of USB interface is 500mA. If the working current of your LED lamp does not exceed 500mA, the series resistance is determined by the following formula: r = (5-led) / ileduled is the working voltage drop of the LED lamp, iled is the working current of the LED lamp (if it is not a power LED, iled is 15mA), r = (5-3) V / 15mA =
The resistance value of resistor R1 is 4 Ω. The resistance value of resistor R2 is 8 Ω. If it is connected into the circuit with power supply voltage of 4V, what is the total current a and what is the current through R2
How many a, if you want to get the total current of 3a, then you should change R2 into a resistor of how many Ω and connect R1 to this circuit
The resistance value of resistor R1 is 4 Ω. The resistance value of R2 is 8 Ω. If it is connected into the circuit with power supply voltage of 4V, the total current is a, and the current passing through R2 is 1.5A. If you want to get the total current of 3a, you should replace R2 with a 2 Ω resistor and connect R1 into the circuit
RELATED INFORMATIONS
- 1. 4V battery with 100 Ω resistance in parallel, the voltage is only 3.9v, what's the reason? Is it related to the current?
- 2. When the voltage at both ends of a resistor increases from 2V to 2.8V, the current through the resistor increases by 0.1A, then the resistance value of the resistor is () A. 8 Ω B. 20 Ω C. 28 Ω D. cannot be determined
- 3. 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?
- 4. 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)
- 5. 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．
- 6. (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
- 7. How to prevent oxidation of wire joint, copper wire and aluminum wire joint
- 8. Why can't we screw copper and aluminum wires together to connect the lines
- 9. 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
- 10. 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?
- 11. In the circuit shown in the figure, the resistance value of resistor R1 is 5 ohm, the current indication is 0.6A, and the voltage at both ends of resistor R2 is 2.5V Find the retention of & lt; 1 & gt; R1, the current of & lt; 2 & gt; R2, the resistance of R2, and the total resistance of & lt; 3 & gt; circuit
- 12. When 18V voltage is applied to a certain section of conductor, the current passing through it is 0.6A, then the resistance to the body is () ohm. If 9V voltage is applied to this section of conductor, the current passing through the conductor?
- 13. As shown in the figure, the power supply voltage is 9V and remains unchanged, the range of the ammeter is 0 ~ 0.6A, and the resistance of the small bulb is 9 Ω, in order not to let the current in the circuit exceed the electric current What is the minimum value of sliding resistor in the circuit?
- 14. After a 3V, 15W small bulb is connected in series with a 2 ohm resistor, the small bulb lights up normally Seek 1: resistance R of small bulb 2: Voltage across resistor R2 3: If the small bulb is directly connected to the power supply, the small bulb will not be burnt out
- 15. When an unknown resistance is connected to the power supply in series with a 6 Ω resistance, its voltage at both ends is 4V; when it is connected to the same power supply in series with a 9 Ω resistance, its voltage at both ends is 3V
- 16. The resistance of an electric lamp is 10 ohm. The normal operation is that the voltage at both ends of the lamp should be 5 V, but the current power supply around us is 8 v How much resistance does it need to connect in series to make the lamp work normally?
- 17. In the circuit, what are the burnt out appliances, ammeters and voltmeters equivalent to? Are they wires or switches?
- 18. An ammeter is equivalent to a wire. What is a voltmeter equivalent to?
- 19. How to judge which electric appliance or circuit is measured by Voltmeter and ammeter
- 20. In refitting the ammeter, wouldn't it be short circuited by connecting a resistor to the ammeter