Hello.

The question is quite simple about the power of the resistors.

Ohm's Law says that when directly connected to 9 volt batteries (power adapters), the minimum resistor resistance at 1 / 4W = 324Ω and 648Ω at 1 / 8W.

At a voltage of 18V, these values are 1.296kΩ for 1 / 4W and 2.592kΩ for 1 / 8W.

It seems that everything is simple and clear, but often in power schemes I see resistors with a value of 10 Ohm-100 Ohm with a power of 1/4 watt.

There are such resistors in

1) Power filtering (many projects Madbean 1N4001 + 10ohm resistor).

2) In "amplifier in a box" projects, when they put an RC filter between the stages and use 100 Ohm resistors (Dr Boogie).

3) Separation of the power section, between the analog part and the BBD, for example, in the BOSS(CE-2 & DM-2) pedals there are 22Ohm-33Ohm resistors.

All these resistors are 1/4 watt, they are much lower than the minimum value calculated according to Ohm's law and they are connected directly to the voltage. Why do they work and do not burn out and how to calculate their power correctly?