Walter,
What voltage are you feeding this with? I assume it is more than
24v in order for you to have a 24v position.
If you are running in the 10 volt position, for instance, that would be
drop of at least 24v - 10v = 14v. Fourteen volts at .5amp is 7W being
dropped into that transistor. That's a pretty fair amount of heat.
tim ab0wr
On Fri, 09 Mar 2018 06:17:16 -0800
"Walter" <W9KJO@...> wrote:
On Wed, Feb 21, 2018 at 06:23 pm, LKNDAVE wrote:
i did the hokie pokie and this jpg came out
Based on this design I built this attached circuit.
It controls voltage nicely.? Really helps limit output power while
working digital.
However the TIP 142 really generates some heat.? I have a heat sink
on it but it will need to be much larger.? it is only drawing
about .5 amp (1/2 amp) while transmitting.
Does that seem normal?? it the heat something I should be concerned
about?? Or just provide a better heat sink and run it?
Thanks for the circuit idea and plan.
?
--
73, W9KJO
Walter
