A 120V power supply connected to a 30 Ohm resistor will produce 120/30 or 4 amps of current.
Please help!
I= V/R
I=120/10
I =12 A
12
When a resistor and an inductor are both connected to an AC supply, the current in the resistor is in phase with the voltage, while the current in the inductor is a quarter-cycle (90 degrees) behind. Supposing they both draw 1 amp on a 12-volt AC supply. The resistor will dissipate 12 watts, while the inductor will dissipate no power. Any power that enters the inductor comes back to the generator in a later part of the cycle. But the current drawn from the supply is 1.414 amps, so this would be a load with a power factor of 0.707.
A rheostat is the name given to a variable resistor when it is used to control current. When a variable resistor is used to control voltage, we call it a potentiometer.A rheostat is connected in series with a load, and two of its three terminals are used. A potentiometer is connected in parallel with the supply, and each of its three terminals are used.So the terms 'rheostat' and 'potentiometer' are the names given to describe the function of a variable resistor, not the variable resistor itself.
opposes changes in current
If there's nothing else between the ends of the resistor and the power supply, then the voltage across the resistor is 24 volts, and the current through it is 2 amperes.
The ammeter is reading zero because there is no current flowing. This is because one of the resistors is faulty; the faulty resistor has an "open circuit" (open circuit means there is a broken connection). We know that: Ohms law is: V = I x R (voltage = current x resistance) Therefore because there is zero current in each resistor there will be zero voltage across each resistor. However we also know that: Kirchhoff's voltage law is: V1 +V2 +V3 + … = Vs (the sum of the voltage drops accross each component in a circuit MUST equal the supply (or battery) voltage). But if all the resistors are zero volts, then what component equals the supply (or battery) voltage? The battery voltage is developed across the open circuit… therefore the resistor which is faulty will have a voltage across it equal to the battery voltage. That easy to measure with a volt meter! hope this helps
If a 9V supply is connected to a 100-ohm resistor, then the current is not 2 Amps,or even close to it.I = E/R = 9/100 = 0.09 amp.
V=IR, V=120 VOLTS R=30 OHMS I=V/R, I=120/30, I = 4Amps
When a resistor and an inductor are both connected to an AC supply, the current in the resistor is in phase with the voltage, while the current in the inductor is a quarter-cycle (90 degrees) behind. Supposing they both draw 1 amp on a 12-volt AC supply. The resistor will dissipate 12 watts, while the inductor will dissipate no power. Any power that enters the inductor comes back to the generator in a later part of the cycle. But the current drawn from the supply is 1.414 amps, so this would be a load with a power factor of 0.707.
4 resistors were connected in parallel it yields 5A of current from 220V supply.
The 12V battery connected to the 2.4 Ohm combination will supply 12/2.4 or 5A. The individual currents will be 12/3 or 4A for the 3 Ohm resistor, and 12/12 or 1A for the 12 Ohm resistor. The 2.4 Ohm parallel combination is obtained from a simple product-over-the-sum calculation.
The equation for such circuits is given by: V=R*I +(1/C)*Integration(idt)
When a dc supply is connected to a resistor, current flows. The current in amps is equal to the supply voltage divided by the resistance in ohms. The power used is the voltage times the current, and that appears as heat in the resistor, which might become hot to touch.
You can measure the current and power of a 'power supply', using an ammeter and a wattmeter. With the power supply connected to its load, the ammeter must be connected in series with the power supply's input. The wattmeter's current coil must also be connected in series with the power supply's input, and its voltage coil must be connected in parallel with the supply, taking the instrument's polarity markings into account.
The electric heater is basically a resistor, designed to have the right resistance to draw the required current. So a 2 kW heater designed for a 230 v supply is really a resistor of 28.8 ohms, so when it's connected the current is 8 amps and the power is 2 kW.
An LED usually has a resistor connected in series with it because an LED (light emitting diode) is not linear in current to voltage (like a resistor) and has to be operated within specified current and voltage conditions. In most circuits the supply voltage is higher than the forward voltage of the LED so the LED would burn up from too much current without a current limiting resistor in series. The resistor sets the voltage and current to a good operating point (voltage and current) for the LED by dropping some voltage across it. The operating point varies depending on the size, type and manufacturer of an LED so the LED's data is used to select the right resistor size for a given voltage source.
Two 6-ohm resistors in parallel have a net effective resistance of 3 ohms.With 3 ohms connected across a 12-volt supply, the current is 12/3 = 4 amperes.
A rheostat is the name given to a variable resistor when it is used to control current. When a variable resistor is used to control voltage, we call it a potentiometer.A rheostat is connected in series with a load, and two of its three terminals are used. A potentiometer is connected in parallel with the supply, and each of its three terminals are used.So the terms 'rheostat' and 'potentiometer' are the names given to describe the function of a variable resistor, not the variable resistor itself.