Newbe - problem with Series Reg Tip 3055 + Z-Diode***HELP**

[Enzo]

I am sure that works fine, but perhaps people needing assistance in basic power supply repair are confused or put off by circuit requirements such as the notes printed top, bottom, and right side of that drawing.

 

[Elvee]

Hi Elvee,

thanks to you too!! This is really a interesting alternative. I should have have seen this before I'm not sure to restart the project from scratch. But the PWM approach is the most effective of course.



Maybe I finish one first and then...Do you have an robust design in use since longer time? Since I use the circuit in a vehicle (Heat, vibration some voltage stress)

I didn't build this exact circuit, but earlier in my career I was a designer of automotive electronic function blocks and modules, and I know pretty well the pitfalls and potentials problems associated with this environment.
The circuit as it is is not fully ruggedized, because it doesn't perform a life critical function.
It will be rather robust though: it will survive polarity reversals because of the 100 ohm and because the MOS+diode should blow the fuse safely.
It will survive short voltage spikes, typically 100V for 2ms, and an absolute maximum of ~170V, which is unlikely because of the 2200µ.
It with also withstand an absolute minimum of 20V permanently, and more probably ~35V, since most CMOS circuits avalanche at >30V, and the avalanche is not destructive if it doesn't exceed the dissipation rating of the chip (700mW).
You could add a 15V transil across the 40106 supply and a 30V varistance across the general supply to improve matters further, but it is really optional.

The heat, stress and vibrations are your responsability: you have to choose suitable components and assemble them appropriately (that is true for any implementation).

Note that a linear regulator having to dissipate tens of watts will suffer severely in those conditions.