resistor parallel


I need

100ohm 3 watt resistor

but cannot find it in market, in market I find 100ohm 1watt resistor

,plz tell me how I acquire (100ohm 3 watt resistor) value.

can I parallel three 100ohm 1 watt resistor to get my value

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-max-2 years ago

Man, that was a sad read. I never would have known, (assuming it is true what is written there.) Well shit happens, if Dilbert comics mean much, it seems to exist everywhere. :(

-max-2 years ago

True, considering these days thing are engineered to fail, quite literally in many cases! Though that really is only true in consumer gear, if I was engineering laboratory testing equipment, where price is not a priority, I can't imagine the same mentality hold true, when a companies (like tektronix or fluke) rely in their high reputation and must deliver good stuff. I do have a NASA internship coming this summer, maybe I will get started on my career through NASA, IDK. That's is certainly a case where engineering to fail is a big NO-NO.

You could use 3, 300 Ohm resistors 1W in parallel. Or 3 , 33Ohm resistors in series.

You CANNOT put 100 Ohm in parallel.

+1. I wouldn't say "can't", but in terms of paralleling 3 100 ohm resistors and expecting to get a 100 ohm combined load, nah that definitely won't work. my defence, I was replying to the OPs comment

can I parallel three 100ohm 1 watt resistor to get my value

Simply, no, you cannot.

sorry, no offense, I was simply commenting. You are absolutely correct.


-max-2 years ago

IDK, but I like to have some engineering margin! That is never a bad idea if you can afford it.

-max-2 years ago

No, that was v=i*r, where I simply plugged in the numbers for R, and divided both sides of the equation by 22, after plugging in the numbers. That is just the way I learned to do it. The ohms law pyramid could also be used, I forgot to cover that in the video. Yeah, I have a tendency to do things the hard way, in this case, on purpose so that whoever is watching can understand the algebra step-by-step.

-max- -max-2 years ago

But thanks for watching it and pointing out mistakes. If a major mistake is spotted, I'll remove the video and 'patch it up.'

-max-2 years ago

I just forgot to show that the 22's on the one side "cancel out" but anyone that has taken 5th grade math should see that, and 12 / 22 simplifies down to 0.545454....A, or 545mA.

-max-2 years ago

Skip to 6:27 to see how to figure out what resistors you need to wire in parallel and/or in series.

iceng2 years ago

If you only have a bunch of 100 ohm 1/2 watt resistors then you can easily make a 100 ohm 4.5 watt Resistor out of nine of them, which is better then a 3W

-max- iceng2 years ago

Just keep them spread apart some to allow airflow over them! If they bundle up and snuggle together too close, they may get a little too warm!

seandogue iceng2 years ago


unless that 3W load is also acting as a failsafe.... But you're right in principle

btw did you get an orange board query on this as well?

iceng seandogue2 years ago

Just only yours.

verence2 years ago

I agree with steveastrouk, but ... "CANNOT" is a hard word...

It needs a lot of resistors (i.e. 9) 100 Ohm resistors, but is IS doable.

three of 100 Ohm resistors in parallel. That' give you the equivalent
of one 3W, 33.3Ohm resistor. Then put three of those paralleled groups
in series. Ta-dah! The equivalent of one 100Ohm, 3W resistor.

Or you could put three strands of three 100 Ohm resistors in series in parallel.

For higher power needs, just think bigger like 4x4 for 4W or 10x10 resistors for 10W.

Of course that all only makes sense if you already have the resistors or can get them much cheaper than the nominal ones. my defence, I was replying to the OPs comment
can I parallel three 100ohm 1 watt resistor to get my value

Simply, no you cannot.