Re: Variable power control

Walter
 

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

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