"Output" resistors(quick Q)?

[mats73]

Would there be any disadvantages in using 4 paralleled resistors with a value of 0,68 ohm instead from the standard 6 resistors with 1 ohm value(the 4 resistors would be rated at 5 Watt)?

(It is for an Aleph 60)

[mpopovics]

You can use it, without any problem, if the paralelled value is the same.
BR,
Milan

[mats73]

Well, its not exactly the same, but I guess it is within the tolerances.
1/6=0,16666...
1/(4/0,68)=0,17

Just about 2 percent off and power rating 20 Watt instead of 18 so I guess it should be fine then.....

[uli]

Don´t forget that every Fet needs its own resistor!

Uli

[mats73]

I don´t mean the resistors that are on the same boards as the Fets, but the resistors named R22- R27 on the "main" board of the Aleph 60.

[uli]

hi mats,
it´s up to you, even 2 0R33 parallel is ok as long as
their power handling ability is twice as high as the possible
power they have to handle.
Example:
10A x 1.65V = 16.5W -> each resistor should be 15W + to
be on the safe side.
You can calculate maximum current thru these resistors by
bias current divided by (1 - current gain of the CCS)
ALEPH2: 3 / (1 - 0.69) = 3 / 0.31 = 9.68 A.

Uli

[jh6you]

Originally posted by mats73
1/6=0,16666...
1/(4/0,68)=0,17
power rating 20 Watt

No reason to hesitate.

JH

[Nelson Pass]

It'll work fine. Tolerance need only meet about 10%.