Ohms Definition and 67 Threads

I am trying to determine ohms and wattage of R2 on attached schematic. The resistor fried so I can't tell anything about it This circuit is a recharger for a cordless black and decker drill Thanks

Homework Statement Graph of current vs voltage. What is happening to the resistance after the linear portion of the graph and why. Homework Equations none The Attempt at a Solution the line is the resistance and it follows ohms law for a while (it is constant and independent...

After seeing contradictory posts on many forums , and getting differing opinions from my teachers , I'm completely lost with the ohms law... I have a number of questions. Can someone please answer them for me? 1) Do semiconductors obey Ohms law? and why do they obey/not obey? if they obey...

2 terminals of a battery are connected to 2 50k ohms resistor...but in open circuit. i.e - ______ ---------/\/\/\/\/\/---|______|--------/\/\/\/\/\/\/\/----- ______ the...

Homework Statement how do you convert watts into ohms? Homework Equations The Attempt at a Solution

Homework Statement Define resistance and resistivity? A 30W, 6A bulb has a filiment which is directly prortional to the absolute temperature? At 37 degrees celcius the reisitance of the fimament is 015ohms. What is the working temperature of the filament? Homework Equations None...

So what produces a solenoid's magnetic field? Voltage or Power? Voltage = Current * Resistance Power = Current^2 * Resistance Magnetic field magnitude of a solenoid = magnetic constant * turns * current We can quadruple the turns using the four times of the same type of wire, but that will...

Homework Statement Calculate the equivalent resistance of the network shown in the diagram. The resistances are: R1 = 12 ohm, R2 = 5 ohm, R3 = 15 ohm, and R4 = 15 ohm. no prob here Req = [(1/12)+(1/5)+(1/15)]^-1 + 15 = 17.86ohm When a battery with E = 6 V and zero internal...

Homework Statement a power station delivers 520kW of power to a factory through wires of total resistance of 3 ohms ,how much less power is wasted if the electricity is deliverd at 50,000V rather than 12,000V Homework Equations P=IV=I^R =V^/R The Attempt at a Solution I tried to...

Homework Statement A 20 ohm platinum wire at 20 C with a temperature coefficient of resistivity of 3.9 x 10 ^-3 /C will have what resistance at 100 C? I know how to answer this in watts and I get 26 W, but for some reason my only options are in ohms. how do i convert Watts to ohms? i...

Alright, I'm a student and doing a science fair experiment for a little extra credit. Here's the link to where I found it online. http://www.sciencebuddies.org/mentoring/project_ideas/Elec_p019.shtml?from=Home I don't get it, at all. I just tried it and every time I measured it the Ohms...

I have this problem I just can't figure out. Current = A (Ampere) i(t)=z(e^t/(RC)) where z is the initial current at t=0, R is the resistance in Ohms and C is the capacitance expressed in secondary units as F (Farad) - Express the units of F in terms of seconds and ohms So, this...

I have looked thought all my notes and books and can not find the formal on how to do this question. I'm slowly going out of my mind any help would be great Calculate the maximum current a 140 ohms, 1/2 watt resistor can have flowing through it safely. Enter answer: mA Then...

"Iron core energy change" and "transformers vs. ohms law" Ooh yes, I do have two question. So enjoy the meal all physics lovers! :smile: 1. If the field is increased putting an iron core inside the circuit, then what about energy conservation? (I don't know much about H-fields.) 2...

What is the name of the device used to measure ohms? :confused:

I have just purchased some thermistors (NTC 50,100,250 ohms). I want to wire it with a led. so it will controll the leds light output with changing temp. I have already tried both series and parrallel configurations. the series confguration does not work at all. In parrallel configuration...

A 3Ohm and a 1.5 ohm resistor are wired in paralles and the combination is wired in series to a 4 ohm resistor and a 10 V emf device. The potential difference on across the 3 ohm resistor is? I reduced the 2 in parrallel to 1.875 ohms and then addes the 4 ohm, which gave me a total...