I do find the 1/2 W resisters to fit better into breadboards

If you're buying parts from known manufacturers, the lead diameter on 1/4W and 1/2W resistors are the same.

From Yaego:


If you're buying cheap resistors, they're more likely to have skinny leads. I got a lot of about 50,000 1/4W resistors that were packaged about a dozen in a plastic bag for some kit on eBay 15 years or so ago (before counterfeits became such a huge problem) and the leads are too skinny. I stopped using them for breadboarding because the leads were too wimpy and almost always bent from the insertion force. I only use them in PCBs now.

If you're buying high quality resistors, the leads will be the normal diameter.

Even these lower tier resistors Jameco sells have the expected lead diameter:



Note that Yaego has something called "miniature" and the Chinese manufacturer has "small size". These are resistors with the formerly standard sizes that are rated for twice the power. So, a "miniature" MFR25S is the size of a regular 1/8W resistor but is rated for 1/4W.

 

When you are finished breadboarding a project, do you throw away the used resistors considering how inexpensive they are?
Not me. I put all the components back in their designated drawers to be used again.
Consider what it must be like to sort through a few hundred resistors. I have done this many times.
E12 ±5% are a lot easier to sort.

Good point I sort with an Ohm Meter. I dont even think about using those colors.

 

I dont even think about using those colors.

You should. It will come in handy if you need to know the value of a resistor that's soldered on a board. A meter might not work in that case.

When I read the color code on resistors, I read numbers, not colors.

 

Welcome to my world, I'm colorblind. IF there is enough area, I can determine the color, but the tiny bands on resistors are very tough for me. That and there is no consistency in the various colors and their hues that are used. I would imagine there is a color hue standard somewhere but not particularly follwed in manufacturing. I keep a small tester handy on the bench.

 

If you're buying parts from known manufacturers, the lead diameter on 1/4W and 1/2W resistors are the same.

From Yaego:
View attachment 258126

If you're buying cheap resistors, they're more likely to have skinny leads. I got a lot of about 50,000 1/4W resistors that were packaged about a dozen in a plastic bag for some kit on eBay 15 years or so ago (before counterfeits became such a huge problem) and the leads are too skinny. I stopped using them for breadboarding because the leads were too wimpy and almost always bent from the insertion force. I only use them in PCBs now.

If you're buying high quality resistors, the leads will be the normal diameter.

Even these lower tier resistors Jameco sells have the expected lead diameter:
View attachment 258128
View attachment 258127

Note that Yaego has something called "miniature" and the Chinese manufacturer has "small size". These are resistors with the formerly standard sizes that are rated for twice the power. So, a "miniature" MFR25S is the size of a regular 1/8W resistor but is rated for 1/4W.

Good to know. The only company I'm familiar with and trust is Vishay. We did all our aircraft strain gauging with Vishay strain gauges and I trust them as a quality company. Plan is to use my cheep stuff to develop the circuit than order Vishay resistors when I have it all sorted. Its good to have a cheep Chinese kit, with 1000 resistors for $14, for development because every time you need to try a different size you can be assured to have them available. Then when you have it down you buy 10 quality resistors for $2 + $8 shipping.

 

You should. It will come in handy if you need to know the value of a resistor that's soldered on a board. A meter might not work in that case.

When I read the color code on resistors, I read numbers, not colors.

That's if I can see them. But I will say 3 bands vs 4 would make it a lot easier.

 

you buy 10 quality resistors for $2 + $8 shipping.

If you're going to be a serious hobbyist, you should order resistors in at least qty 100 to get a price break. That's what I did until I started buying liquidated stock from businesses.

To save on shipping, order enough at one time to make shipping a smaller percentage of the purchase.

But I will say 3 bands vs 4 would make it a lot easier.

What makes you think that?

 

I often use higher wattage resistors than I need when I place a resistor above the board. (because of the thicker leads)

By "above" I mean having a space between the resistor and the board.

 

Wouldn't the larger of two resistors of identical materials and construction eg. 1/4W to 1/2W have additional inductance and capacitance (in themselves and interactions due to proximity) however small a value? I've noticed strange behavior with just a piece of short wire which has almost zero R/L/C as far as I know which prompts the investigation especially for high frequency applications. I've found a few sources that touched on this but nothing definitive.

 

When I started working with Arduino, I purchased an assortment of 1/2W resistors. Now that I have a design nearly complete and starting to see there real power requirements, I can see that most cases my power is well under 1/8W. So I was wondering if I should be concerned about using resistors of a higher power value than required. Should I just use my 1/2W for everything or is there an advantage to getting a stock of 1/4 W and 1/8W and install them appropriately. Is there any margin of safety that should be maintained or some percentage range I should stay between.

John

The standard rule of thumb is to size your resistor twice as big as whatever power it is expected to handle. Remember, a Resistor slows current through friction so it gets warm. It is rated as it is in order to dissipate that heat reasonably well, so things don't overheat.

While you're learning, go ahead and use your half-watters. But start obtaining 1/8 and 1/4 watt resistors as well. Don't worry, you'll need them all. Resistors are typically the largest component count on any given project.

I have over 78 THOUSAND resistors in my inventory. Everything from sub-1 Ohm, to 15M-Ohm, and 1/8-Watt to 20W.

 

Wouldn't the larger of two resistors of identical materials and construction eg. 1/4W to 1/2W have additional inductance and capacitance (in themselves and interactions due to proximity) however small a value? I've noticed strange behavior with just a piece of short wire which has almost zero R/L/C as far as I know which prompts the investigation especially for high frequency applications. I've found a few sources that touched on this but nothing definitive.

A single piece of wire is called a 'shunt' where it's being used as a resistance. Look for shunts

 

I switched from using 1/2W resistors with vacuum toobies 58 years ago when I began designing and building transistors circuits with 1/4W resistors.
I never used a Mickey Mouse solderless breadboard for prototypes because in my job and hobby the prototypes were built and soldered on a compact stripboard and were sold and used as the finished product.

 

Just remember, resistors have characteristics, choosing the correct type is equally important.

 

Using over-rated Resistors helps to keep the over-all Heat down on the Board.

BUZZZ

To the TS: It keeps the *temperature* down. The heat dissipated is exactly the same no matter what the wattage rating or physical size.

ak

 

No kidding ......
I would never have guessed,
I'm so grateful for your generous correction.
.
.
.

 

My comment had two purposes. It has served the first, so I updated it.

ak

 

That us exactly what I was objecting to, the incorrect use if the word “heat”, instead of “temperature”. I should have been more explicit.

Bob