1/8(0,125)Watt resistors in 9v pedals?

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1/8(0,125)Watt resistors in 9v pedals?

Postby POTL » 12 Aug 2017, 17:29

Can I use such resistors in pedals?
Or at least it is 1/4 Watt
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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby alexradium » 12 Aug 2017, 17:54

sure,Marshall did it,worked fine.

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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby POTL » 12 Aug 2017, 18:06

alexradium wrote:sure,Marshall did it,worked fine.


Great
Does this apply to the new Marshall?
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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby POTL » 12 Aug 2017, 18:10

Also I noticed compact resistors in EQD pedals, as I understand it is also 1/8 watt, am I right?
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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby ppluis0 » 13 Aug 2017, 02:19

Hi folks,

If we connect a 680 ohms resistor across the contacts of a fresh 9 Volt battery, the dissipation in that resistor is only 119 mW

So, resistors of higher value than 680 ohms dissipate consequently less power than 1/8 W in stompboxes working at 9 Vdc... 8)

Cheers,
Jose

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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby POTL » 13 Aug 2017, 08:10

ppluis0 wrote:Hi folks,

If we connect a 680 ohms resistor across the contacts of a fresh 9 Volt battery, the dissipation in that resistor is only 119 mW

So, resistors of higher value than 680 ohms dissipate consequently less power than 1/8 W in stompboxes working at 9 Vdc... 8)

Cheers,
Jose


This is considered subject to the connection to the network 9 volts.
It turns out that values ​​less than 680m can be used when connecting to the ground or the sound part, the main thing is not to connect directly to the power (half-power again, it does not concern.
I'm right?
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Re: 1/8(0,125)Watt resistors in 9v pedals?

Postby deltafred » 13 Aug 2017, 12:47

POTL wrote:I'm right?

From a power rating point yes you are right.
I would think (without breaking out Kirchoff's Law on all resistors in a pedal) that you can use 1/8W resistors in 99.99% of cases.

There are probably exceptions in some power supply polarity protection circuits. If the safety of your pedal relies upon a low value resistor (+ diode) shunting an incorrect polarity power supply down to a level that does not damage the semiconductor devices then it will be best to calculate the maximum dissipation and add a safety factor.
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