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#### Rikard Bosnjakovic

- Jan 1, 1970

- 0

Consider a 10v-circuit with a 1A-load. This gives 10W dissipation (P = U*I

= 10 * 1 = 10).

Suppose I then want to strangle the current down to 0.5A. Ohm's law gives

me R = U/I = 10/0.5 = 20 ohm, so I add that one. With 0.5A load, the

dissipation is 10 * 0.5 = 5W.

For the sake of easy calculation, let's assume the circuit is perfectly

linear. Now for the question: Should the resistor be 5W, i.e. the latter

value above, or 10W, the first value?

I tried to figure it out but couldn't come up with a reasonable answer of

why I should pick the one or other size.