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

PostPosted: 12 Aug 2017, 17:29
by POTL
Can I use such resistors in pedals?
Or at least it is 1/4 Watt

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

PostPosted: 12 Aug 2017, 17:54
by alexradium
sure,Marshall did it,worked fine.

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

PostPosted: 12 Aug 2017, 18:06
by POTL
alexradium wrote:sure,Marshall did it,worked fine.


Great
Does this apply to the new Marshall?

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

PostPosted: 12 Aug 2017, 18:10
by POTL
Also I noticed compact resistors in EQD pedals, as I understand it is also 1/8 watt, am I right?
4934411462_7039db678a_b.jpg

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

PostPosted: 13 Aug 2017, 02:19
by ppluis0
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

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

PostPosted: 13 Aug 2017, 08:10
by POTL
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 ‚Äč‚Äčless 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?

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

PostPosted: 13 Aug 2017, 12:47
by deltafred
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.