0
A 30 Ohm resistor is connected to a 4-V supply How many watts will this resistor have to dissipate?
Wiki User
∙ 14y ago
P = V*I, and V = I * R, so:
P = V^2 / R:
P = 16/30 = ~.5 watts.
Wiki User
∙ 14y ago
kevin datadeen
Anonymous
7.5
Add your answer:
Earn +20 pts
What voltage will cause a 20 Ω resistor to dissipate 5 Watts?
10V
A three-phase heater dissipates 15 kW when connected to a 208 V three-phase line Determine the value of each resistor if they are connected as star?
It took me a while to find out what a star connection is. In the US we call it a Y connection. Each resistor has to dissipate 1/3 of the power, or 5000 watts. then it's just a case of using P=E2/R. or R =E2/P R = 208 x 208 / 5000 = 8.66 ohms
What is the current running through a resistor of 9 ohms with volts of 90?
I = E / RIf the voltage across the resistor is 90 volts, and the resistance of the resistoris 9 ohms, then the current through the resistor is90/9 = 10 Amperes.Don't try this at home!The power dissipated by the resistor is E2/R = (90)2/9 = 900 watts. That's comparable to the power (heat) dissipated by a small toaster. A common composition resistor will get hot and possibly explode if it's asked to dissipate that kind of power.
If a 100 ohm resistor is needed in an electric circuit carrying a current of 0.3 amperewhat resistor would you select?
A 100 ohm resistor carrying a current of 0.3 amperes would, by Ohm's Law, have a potential difference of 30 volts. A current of 0.3 amperes through a voltage of 30 volts would, by the Power Law, dissipate a power of 9 watts. You need a 10 watt resistor, alhough it is better to use a 20 watt resistor. E = IR 30 = (0.3)(100) P = IE 9 = (30)(0.3)
If 3 15 ohm resistors are connected in parallel to a 30 volt battery what is the equvalent resistance through the circuit?
5 ohms...
When an inductor and resistor are connected in parallel by how many degrees is the current flow through the resistor out of phase with the current flow through the inductor?
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 resistor Connected to a 9 Volt supply dissipates 3 watts calculate the value of the resistance?
about 27ohms
What applied voltage will cause a 20 Ω resistor to dissipate 5 Watts?
10V
What voltage will cause a 20 Ω resistor to dissipate 5 Watts?
10V
What does the physical size of a colour-coded resistor indicate?
the physical size tells how much power it can dissipate (watts)
How many watt values are there for resisters?
Some of the more common values are 1/8, 1/4, 1/2, 1 and 2 watts. On PC boards the larger resisters are not placed adjacent to the board but connected into the board above the board using standoffs. This is to let air circulate around the resistor to carry away the heat generated by the resistor. The physical size of the resistor reflects the resistors ability to dissipate the heat which builds up inside the resistor. As the wattage goes up so does the physical size of the resistor. Resistors that dissipate very large amounts of power (watts) are usually wire-wound resistors. Wire-wound resistors can be as high as 100 watts.
What will a 12 ohm resistors temperature be when 12 volt is applied?
A 12 ohm resistor with 12 V across it will dissipate 12 watts. To determine the temperature of the resistor, you need more information. The resistor and 12 V supply could be inside an oven, in which case it would be very hot, or in Antarctica, in which case it would be very cold.
What wattage of heaters would you use if 2 are wired in series with 120 vac to equal same as 2 heaters of 210 wattage each wired in parallel?
-- Two loads ... each of which dissipates 210 watts on a 120V supply ...when wired in parallel, dissipate 420 watts.-- Two others in series also want to dissipate 420 watts, so each of thosedissipates 210 watts on a 60V supply.Power dissipated is proportional to the square of the voltage, so on a 120V supply,each of these would dissipate 840 watts .
Resistors allow electrical energy to be changed to other forms of?
All a resistor does is use electrical energy, converting it to heat. so a 10 ohm resistor with 5 volts across it will dissipate 2.5 watts. this will come out as heat, ie, the resistor will get hot.
How can you measure the ampere or watt for power supply?
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.
What is the result in voltage of applying a 2.7 ohm resistor to a 12 volt DC circuit?
The question has just stated clearly that the applied voltage is 12 volts DC.Provided that the power supply is capable of maintaining its output voltage while supplying some current ... i.e. that the effective internal resistance of the power supply is small ... and that the 2.7 ohm resistor is the only external element connected to the power supply's output, the voltage across the resistor is exactly 12 volts DC.The current through the resistor ... supplied by the 12 volt DC supply ... is 12/2.7 = 4.44 Amperes (rounded).The power dissipated by the resistor ... supplied by the DC supply ... is 122 / 2.7 = 53.23 watts !
A three-phase heater dissipates 15 kW when connected to a 208 V three-phase line Determine the value of each resistor if they are connected as star?
It took me a while to find out what a star connection is. In the US we call it a Y connection. Each resistor has to dissipate 1/3 of the power, or 5000 watts. then it's just a case of using P=E2/R. or R =E2/P R = 208 x 208 / 5000 = 8.66 ohms
