[Amps] Grid protection resistors

[R L Measures]

On Jun 26, 2006, at 1:46 PM, Tom W8JI wrote:

> By the way, NEVER use a resistor to protect sensitive
> expensive devices.

3-500Zs are apparently tougher than 1/4 and 1/2 w carbon film resistors.
>
> Fuses are bad enough. They have a very slow failure period
> as they melt and then open. The time is also dependent on
> temperature and even the age of the fuse, but it can be a
> very long time at 200% overload.
>
> The grid often will protect a fuse, rather than a fuse
> protecting a grid.

Not for a 3-500Z with a 30-ohm 1/4w carbon film R grid fusing element..
>
> Anyone who understands anything about resistors would also
> know a metal film resistor can take a pretty severe overload
> before opening.

Quite true, Tom

> ...

R L MEASURES, AG6K. 805-386-3734
r at somis.org