1/4w VS 1/8w resistors

[David665]

If I've rwad and understood it correctly,1/4w resistors can be used in place of 1/8w resistors with little issue, but not vice versa, correct?

[vizcities]

In the case of most pedals, they're basically interchangeable.

[Zerro]

Because of almost the same size, it is more usefull to use resistor for higher duty, to have some reserve. If power is mean question here. Maybe I should better to consider if they are metallised or old graffit type. Metalised ones has much lower innert noise, and higher temperature stability. For audio circuits, even with high gain (boost), it is important choice. Especially when at gain feedback circuits.

[David665]

Well, I bought a 1/8w and a 1/4w kit, but only the 1/8w showed up. I bought the Donut, Hipstet, Rabbithole and got the Violenzz free. Two use 1/8 and two use 1/4. If I could use the 1/8 in the 1/4 w PCB's, that'll save me a bit of money.

[harryklippton]

I started out buying resistor kits like that (and capacitor ones too) but I quickly found I preferred to bulk order the values I need for projects from tayda or mouser

[Aentons]

If I've rwad and understood it correctly,1/4w resistors can be used in place of 1/8w resistors with little issue, but not vice versa, correct?

The simple answer is... That is correct.


1/8 & 1/4 Watt are the maximum wattage the resistor is designed to handle before it fails (meaning that it turns black and no-worky).

It's usually just a few of the resistors in the power section that actually need a higher wattage rating than the others, so you could get away with subbing to the lower wattage if you know what your doing. I think the general rule is if it's just audio running thru it then you are probably fine but if it's power then you have to be more careful.

Another consideration is that 1/4W can handle double the power but is also double the size so if you use 1/4w on a board that calls for 1/8W there may be space constraints and you would have to stand them up vertically off the board(which is perfectly fine).

[matmosphere]

1/8 are physically a little smaller, so in terms of space they will fit in place of a 1/4. The reverse is not true. A 1/4 watt will not lay flat in the same space as a 1/8 watt. You can certainly fit them but generally with one side raised up a bit.

In terms of power handling I have only seen a few cases in 9v pedals where it matters, but when it does it will be noted in the BOM.

A couple places even sell 1/4 watt resistors that are the same smaller size as 1/8 watt ones.

Look at some of the 1590a boards and build guide and you'll see a little more about the size difference.

[David665]

All four are designed for 1590a enclosures. But it seems the answer is that I need to get 1/4w for the builds that have that in the BOM.

[davent]

I'd guess the the only reason 1/8's are used over 1/4's is the need for room, wattage wasn't even a consideration, if there was room for 1/4's they were used simply because that's commonly what people have stocks of for regular sized builds.

In addition to 1/8w you can get 1/4w, 1/3w, 0.4w, 0.5w, 0.6w & 1w resistors in that ~0.25" length.

https://www.digikey.ca/en/products/filter/through-hole-resistors/53?s=N4IgjCBcoCwGxVAYygMwIYBsDOBTANCAPZQDaIAHBQJwBMIhNArBQyNWLQMxse0y9OTQXADsbGBTAAGCj0Ic4rBWDjVBo6RogrR9BbVoID1Y%2B1rVl56usLxasq9S7Sd7GE2EKPZ6h-EKonD6IJIyFPQAuoQADgAuUCAAynEATgCWAHYA5iAAvoQAtPTQICiQaQCuBMRkIMKReQX1iCAxUGCx7ZC0TM0IpekAJokh8YkpGTlscQCeMbiJQ9goTUA
dave