Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [ohms]

38 questions
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Why is 10W resistor getting hot with only 6.5W running through it?

I am running about 6.5W though a 10W resistor. The ohm rating is 220 ohms, which is correct for the circuit ohms which is calculated to about 225 ohms. Here is what is running through my 220 ohm 10 watt resistor: 38.4 volts 0.17 amps 225.88…
hbsrnbnt
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Where did these Ohms come from?

I am new to electronics and am tyring to figure out something that is a bit disturbing to me. I am trying to figure out the amount of resistance I need to put in series before an LED, and the equation I keep coming across is: $$R = \frac{V_S -…
smeeb
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Why to use Siemens to measure high resistance?

I have a Fluke 87V and I can see lots of EEVBlog videos were Dave measure high resistance values, and instead of using the Ohms range, he goes to the Siemens range (nS actually). My question than is, why the multimeter shows this big values in…
mFeinstein
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How to replace a 50 ohm speaker with 25 ohm speaker?

I'm repairing an electronic device at home. Actually it has a non functional speaker. So I've to change it. This speaker is a 50 Ohm, 0.2 Watt. But I didn't find this one on the market, what I could find is a 25 Ohm, 0.3 Watt. I searched on the…
Billben
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Why can't one battery power an infinite number of leds (or anything else)?

If voltage is equal across parallel resistors, then why can't one battery supply power to a infinite number of leds, if they are all in parallel?
ZackB
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What does S stand for in 75 S ohms?

From the manual for a Repeater unit (page 10 in pdf document). Transmit LIU Waveshape (Build-out) S2-4: ON S2-5: ON S2-6: OFF 75 S ohms w/ High Return Loss S2-4: OFF S2-5: ON S2-6: OFF 125 S ohms w/…
ed-ta
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How many ohms do you need before you need a resistor?

Okay, I'm rather a bit confused here now. I am trying my first real circuits, for some LED lighting. I tried making a little circuit last night, matching two LEDs in parallel on 4.5v of battery. However I didn't make any accounting of the amperage.…
eidylon
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Increasing resistance on speakers

My amplifier is rated at 8ohms for my surround sound but my speakers are 6 ohms. The owners manual says that if the speaker resistance is too low the power protector will blow and that is exactly what happens when I raise the volume on my amp. I…
Derek Eisenberg
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Why can people touch high voltage?

So I know that you need a certain current flowing through you to die, I've heard from some people "its the amps that kills you", and from others "Its the volts that drive the amps" and I realize that these are true according to ohms law v=ir or…
Rhezner
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Convert sonic fuel gauge sender volts to traditional style ohms

I have a late model Harley Davidson Vrod that uses sonar for fuel level. This sonic fuel level sensor outputs volts 0.9v when full to 3.8V when empty. I want to change my instrument cluster but the one I have needs Ohms (0-90) for the fuel gauge not…
calabash
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Resistor/Ohm's law question?

I just used Ohm's law and I was puzzled by this. I am quite new to resistors, and I am only going to use it for an Ionocraft project to reduce the flow of current to ground. So if I have a 9v battery, and had an impossible LED that could get 1 amp.…
user71323
1
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3 answers

Potentiometer - How?

I bought a 5m LED strip from Ebay and connected it to 12V 1.5Amps. I am a starter in engineering. What kind of potentiometer do I need to use to lower or increase the brightness? How many Ohms do I need for it? PS: if there is a formula I`d like to…
FreeBeerOMG
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Principles of Electronics Question Parallel Circuits

In a four-branch parallel circuit, there are 10mA of current in each branch. If one of the branches opens, the current in each of the other three branches is a) 13.3 mA b) 10 mA c) 0A d) either (b) or (c) The book gives the answer as (b). I cannot…
cfehr003
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Total equivalent resistance of this circuit

All resistance are equal in value, \$R1 = R3 = R4 = R5 = R6 = 1~\Omega\$ My calculations are as follows: R1 and R3 are in parallel => \$R13 = 2~\Omega\$ R5 and R6 are also in parallel => \$R56 = 2~\Omega\$ R13, R4 and R56 are in a series => \$R_s…
Vrabii Daniel
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Real output resistance of MOSFET

This question is related to MOSFET. NMOSFET's resistance was till now defined in many different ways, for example as: or which value varies from 1-50k Ohm. And there is also drain-source on-state resistance which is usually lesser than 1…
Keno
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