True.? The standard current limiting supply I described is not something to lean on
to avoid driving the final too hard, that's not what I was suggesting.
If there's a current limit on the finals, should be foldback current limiting:?
? ??
/g/BITX20/message/40719A polyswitch does much the same thing very cheaply,
though the trip point is not quite so well defined.
? ??
/g/BITX20/message/19867I have an old bench supply I found at Goodwill, has voltage and max current adjust knobs.
Very useful when first powering up a new design.
Also useful for things like checking a zener or charging a battery, use it all the time.
Weird that none of the cheap switchers provide either flavor of current limit.
Ideally both, strap selectable.
Jerry
On Thu, Mar 15, 2018 at 03:56 pm, Tim Gorman wrote:
When you current limit the PA you are doing the same thing that happens
when you overdrive a linear amp and cause flat-topping, i.e. the PA is
driven out of its linear range.
That causes spurious products in your transmitted signal.
You would be better off fusing your PA so it can't pull too much
current. Then adjust your drive level so the fuse never blows.
